WELCOME TO THE NIH DIRECTOR'S
WEDNESDAY AFTERNOON LECTURE
SERIES.
I'M THE LEAD THE CELLULAR
COMMUNICATION IN THE CHILD
DEVELOPMENT INSTITUTE AND I
AM
THRILLED TO INTRODUCE DR.
YISHI
JIN, WHO IS CONDUCTING NEW
RESEARCH IN NEURO- CELLULAR
OUR SPEAKER TODAY IS YISHI
JIN, A
DISTINGUISHED PROF. OF
NEUROBIOLOGY AND CELLULAR AND
MOLECULAR MEDICINE AT THE
UNIVERSITY OF CALIFORNIA SAN
DIEGO.
SHE HAS BEEN NOMINATED BY THE
WOMEN SCIENTIST ADVISORS
FIRST
BECAUSE OF HER SCIENCE AND
SECONDLY BECAUSE SHE MENTORED
AND
SERVED AS A ROLE MODEL FOR
MANY
WOMEN, INCLUDING MYSELF.
DR. JIN RECEIVERS
UNDERGRADUATE
IN CELL BIOLOGY FROM PEKING
UNIVERSITY AND COMPLETED HER
PHD
IN MOLECULAR BIOLOGY AT UC
BERKELEY WORKING WITH --
MODULAR
SYSTEM AT -- LABORATORY AND
THEN
SHE MOVED TO MIT FOR A
POSTDOC
WITH -- AND THERE IS WHERE
SHE
STARTED TO USE THE -- AS A
MODEL
SYSTEM.
IN 1996, YIN STARTED HER LAB
AT
YOU SEE SANTA CRUZ AND JUST
FIVE
YEARS LATER SHE BECAME A
HOWARD
HUGHES INVESTIGATOR.
TODAY SHE IS A DISTINGUISHED
PROFESSOR AND CODIRECTOR OF
THE
-- INSTITUTE OF BRAIN AND
MIND
ACCUSES SAN DIEGO AND HER
RESEARCH FOCUSES ON THE
MOLECULAR
GENETICS MECHANISM UNDERLYING
DEVELOPMENT AND FUNCTIONING
DEVELOPING SYSTEM AT FIRST HE
PIONEERED THE USE OF
FLUORESCENCE-- FOR INDIVIDUAL
VISUALIZATION THE SYNOPTIC
STRUCTURES AND THEN TO USE
THE
TOOL TO SCREEN FOR MOLECULES
INVOLVED IN SYNAPTIC FAMILY
AND
DEVELOPMENT AND HER APPROACH
PRACTICALLY ESTABLISHED THE
FIELD
OF MOLECULAR GENETICS AND IN
ADDITION SHE PLAYED AND
INSTRUMENTAL ROLE IN
DEVELOPING
THE LASER, TECHNOLOGY TO
DEVELOP
OUR MODERN RESEARCH ON OXY
REGENERATION IN HER LAP NOT
ONLY
DISCOVERED THE MOLECULAR
REASSEMBLY OR OXY
REGENERATION
AND ALSO -- DURING NERVOUS
SYSTEM
DEVELOPMENT. FOR HER SCIENCE
YIN
HAS RECEIVED NUMEROUS AWARDS
FROM
PRESIDENTIAL EARLY CAREER
AWARD
TO FELLOW OF AMERICAN SOCIETY
OF
ARTS AND SCIENCES; FELLOW OF
THE
AMERICAN SOCIETY OF CELL
BIOLOGY,
AND LAST MONTH MEMBER OF THE
NATIONAL ACADEMY OF SCIENCES.
YIN IS AMONG THE MOST HIGHLY
CITED RESEARCHERS IN THE
UNITED
STATES.
SHE IS ALSO DEDICATED TO
MENTORSHIP AND SCIENCE
EDUCATION;
SHE HAS TRAINED DOZENS OF
YOUNG
SCIENTISTS MANY OF WHOM ARE
NOW
IN TENURE OR TENURE-TRACK
POSITIONS ALL OVER THE WORLD
AND
THE TITLE OF HER TALK TODAY
IS
NEURONAL RESPONSE TO INJURY
AND
STRESS INSIDE -- ELEGANCE.
WELCOME TODAY.
THANK YOU VERY MUCH FOR THAT
VERY
GENEROUS INTRODUCTION, AND
ALSO
THANK YOU FOR NOMINATING ME
FOR
THIS LECTURE AND IT IS REALLY
HUMBLING TO SPEAK HERE,
PARTICULARLY APPRECIATE ALL
THE
SUPPORT OF THE NIH TO MY
PROGRAM
AND AS THE TITLE IMPLIES. I
WILL
COVER FROM THE WORK WE USE, C
ELEGANCE AS A MODEL TO
UNDERSTAND
THE FUNDAMENTAL COMMUNITY
SOME
HOW NEURONS PROTECT
THEMSELVES
THAT I WILL START WITH THIS
CENTURY-OLD IMAGE, QUITE
PLENTY
OF THEM AT UC AT THE NH
CAMPUS
PRODUCED BY RAMON Y CAJAL.
AND THROUGH VERY SYSTEMATIC
AND
EXTENSIVE MICROSCOPY
OBSERVATIONS
-- I AM TRYING TO FIGURE OUT
IF
THIS IS THE LASER.
I'M SUPPOSED TO BE USING THE
LASER ON MY SCREEN?
I THINK YOU CAN SEE THAT.
THAT IS THROUGH A LOT OF WORK
HIMSELF AND HIS STUDENTS,
AND THEY DEMONSTRATED NOT
ONLY
THE NEURON -- AND LATER
EXPLORED
THE CONCEPT OF HOW NEURONS,
HOW
DID THEY RESPOND TO INJURY.
AND THIS IMAGE ACTUALLY SHOWS
THE
DALCAMA (PHONETIC) IN THE
CENTRAL
NERVOUS SYSTEM RESPONDING TO
A
KNIFE CUT AND THE EXONS,
LOOKING AT A SIGN OF THE
DISTROPHIC BULB,
WHICH TRIGGERED A LOT OF
STUDIES
AND SOME CONTRIBUTED TO THE
ENVIRONMENT,
AND SOME CONTRIBUTED TO
INTRACELLULAR DISORGANIZATION
OF
CYTOSKELETON SUCH AS THE
STUDY
DONE BY FRANK BRATSBUG'S LAB
(PHONETIC).
AND IT HAS EVOLVED OVER THE
YEARS
BOTH TO INHIBITING GULLIAR
SCALLS
INHIBITORS AND ALSO MARKER
TUBULAR -- AND TO PROTECT THE
--
TO REGENERATING.
DESPITE OF THESE MANY YEARS
EFFORTS OUR UNDERSTANDING OF
HOW
NEURONS RESPOND TO INJURY
REMAINS
AN INTENSE TOPIC WITH MANY
THEORIES.
I HAVE BEEN WORKING WITH A
MODEL
ORGANISM FOR 20-30 YEARS
PARTICULAR USING NUMATOAD ODS
25TH ANNIVERSARY SCIENTIFIC
SYMPOSIUM HERE.
(CORRECTION)
ODS 25TH ANNIVERSARY --
(CORRECTION)
C ELEGANS.
IN C ELEGANS AXONS GROW
AROUND A
MATRIX AND ARE NOT
MYELINATED,
GENERALLY THEIR MORPHOLOGY IS
RATHER SIMPLE. IN MANY
STUDIES IN
SERENDIPITOUS WAYS WE APPLY
THE
PHYSICS, AND IT WAS A WAY TO
SEVER THE C ELEGANS AXON.
THIS SHOWS A MOVING WHAT YOU
SEE
THIS IS A LASER CUT AND THIS
IS
(INDISCERNIBLE) --
AND THIS BEGINS TO INITIATE
GROSS
CONES AND VERY SPONTANEOUS,
VERY
RAPID BUT THIS REGROWTH IS
ACTUALLY VERY SPONTANEOUS.
DOES NOT ACTUALLY REPAIR
ITSELF
AND CAN PULL BACK TO ITS
DEVELOPMENTAL STATE.
SO WHEN WE ESTABLISHED LASER
AXOLTOMY (PHONETIC) ASSAY,
WE DECIDED TO TAKE ADVANTAGE
OF C
ELEGANS SINGLE CELL AND
DECIDED
TO PROBE INTO THE UNDERLYING
MECHANISM.
THE FIRST THING IS WE KNOW,
GENERALLY CALCIUM IS A FIRST
RESPONDER TO A LOT OF
TRAUMATIC
INJURIES. SO WE USED IN THESE
EARLY STUDIES ABOUT A DECADE
AGO,
WE EXPRESSED THE G COM AND C
ELEGANS NEURONS AS YOU CAN
SEE
HERE FOLLOWING SURGERY
AND YOU CAN SEE THE TRACE OF
CALCIUM AND ORANGE COLOR.
THIS IS ALSO VERY SPONTANEOUS
BUT
WE CAN MEASURE THE TRANSIENT
AMPLITUDE OF CUT SITE TO
TOTAL
GROWTH EXTEND WHERE WE CAN
SEE A
POSITIVE CORRELATION,
AND SUGGESTING THE CALCIUM
TRANSIENT COMES WITH THE
INJURY
LIKELY CONTRIBUTING TO THE
INJURED AXON TO REGROW AND
WE
WERE ABLE TO LINK THE CALCIUM
TRANSIENT TO BULK -- CALCIUM
CHANNEL, AND THIS CALCIUM
TRANSIENT WORKS TOGETHER WITH
SECOND MESSENGER SYSTEMS TO
PROMOTE AXON REGROWTH.
IN MANY WAYS THAT PEACE
PROMOTES
THE PERIPHERAL NERVE TO
REGENERATE AND IT HAS LONG
BEEN
STUDIED IN THE MAMMALIAN
FIELD
PARTICULARLY IN WOLVES AND IN
(INDISCERNIBLE) MANY YEARS
AGO.
MORE RECENTLY WE IDENTIFIED
THIS
RAPID AXON-CALCIUM TRANSIENT
FOLLOWED BY A SLOWER CALCIUM
TRANSIENT IN MITOCHONDRIA
WHICH
DEPENDS ON MITO UNI POLAR,
(INDISCERNIBLE).
---
ADDITIONALLY WE HAVE BEEN
EXPLORING BOTH MEMBRANE
ORGANELLES AS WELL AS
CYTOSKELETON, AND ONE OTHER
VERY
TRADITIONAL MARKERS LOOKING
AT
CYTOSKELETON AS A MICROTUBULE
PROCESS BITING FACTOR CALLED
THE
EBP.
YOU SEE A SINGLE AXON,
PROBABLY ONLY 10-15
MICROTUBULE
FIBERS.
IN THIS MOVIE YOU WILL SEE
INJURY
SITE AND THE EBP:GFP FORMS
WHITE
SPOTS WHICH CONVERT TO THE
CHAMOGRAPH AND THE EBP SITES
CORRELATING TO THE
MICROTUBULE
DYNAMICS.
INJURED AXONS HARDLY SEE EBP
COME
IN AND WITHIN THREE HOURS WE
START TO SEE SIGNS OF
PHILIPODIA
(PHONETIC)
AND WE START TO SEE AN
INCREASE
IN EBP CLASS NUMBERS, IT
BEGINS
TO (INDISCERNIBLE) AND WE
START
TO SEE THE EBP COME IN, FIRST
INCREASE AND THEN SUSTAIN THE
GROWTH IN RUNNING LANS.
WE IDENTIFIED A MOLECULE
CALLED
THE -- A MICROTUBULE
STABILIZING
FACTOR, AND THAT TRIGGERS A
DESTABILIZING (INDISCERNIBLE)
TO
WORK TOGETHER WITH TO
CONSERVE
THE PROTEIN CALLED THE TACC
AND
(INDISCERNIBLE).
THIS FUNDING SUBSEQUENTLY
FOLLOWED BY JAMES FOCET'S
(PHONETIC) GROUP, SHOWS
PERIPHERY
NERVE MAMMALIAN --.
---
I'M GOING TO SET UP THIS
LASER
EXOLTAMY ASSAY TO TAKE AGING
CONSERVATION SCREEN TO LOOK
FOR A
MECHANISM THAT COULD BE
SHARED
-- LOOKING AT THE MAMMALIAN
AXON
REGENERATION FIELD. THE WAY
WE
DID IT IS THAT C ELEGANS
GENERALLY IS IN CODING GENES.
WE HAVE WONDERFUL RESOURCE
COMMUNITY THAT GENERATED LOTS
OF
GENETIC MUTATIONS, AND SO WE
THEN
STARTED CHOOSING ABOUT 1500
OF
THEM THAT WE KNOW COULD BE
EXPRESSED IN THE NERVOUS
SYSTEM
AND COULD BE INFLUENCING AXON
REGENERATION.
IN ALL THESE CASES WE CHOOSE
THE
GENES -- GENERALLY WITHIN
NORMAL
NEURO SYSTEM ARCHITECTURE AND
PERFORMED IT IN LATE LARVAE
ADULT
STAGE LOOKING FOR AXON
REGENERATION RESPONSE, MORE
RESEMBLING THE MAMMALIAN
REGENERATION FIELD.
---
AS SHOWN HERE,
ESSENTIALLY WE SCREENED ALL
OF
THOSE 1500 GENES; THE
MAJORITY OF
THEM ALMOST 80% OF THEM HAD
NO
DEFECT AND WHAT I MEAN BY
THAT IS
SHOWN IN THIS IMAGE.
IN RESPONDING TO INJURY, AND
THE
RED ARROW, THOSE AXONS WILL
INITIALLY REGROW BUT YOU CAN
SEE
THAT IT'S GROWTH IS RANDOM,
ALL
OVER THE PLACE AND THIS
REGROWTH
REPRESENTS A SPONTANEOUS
RESPONSE
TO INJURY.
WE SEE ABOUT 15% OF THE GENES
THAT HAVE LOSS OF FUNCTIONING
IN
THOSE GENES, RESULTING IN A
DECREASE IN THE REGROWTH TO
PROMOTE INJURY RESPONSE AND
THERE
IS NOT MUCH REGROWTH IN THIS
IMAGE VERY LITTLE BRANCHING.
---
ABOUT 5% OF THE GENES ACT AS
AXON
INHIBITORS.
THE TOTAL GROWTH IS MORE
COMPARED
TO (INDISCERNIBLE).
BECAUSE THESE GENES ARE
CHOSEN
BASED ON HOMOLOGY -- YOU CAN
SEE
THIS IN HUMANS FROM GENE
EXPRESSION TO -- AND THIS
SUMMARY
SHOWS THAT USING EACH GENE
GOAL
CATEGORIES, THERE WILL BE
GENES
REQUIRED FOR PROMOTING THE
INJURED ACCENT TO GROW,
AND GENES ACTING TO PROMOTE
THE
REGROWTH, AND AS A
GENETICIST,
AXON REGENERATION FOLLOWING
INJURY IS A PROCESS THAT
SOMEHOW
MIMICS A DEVELOPMENTAL
FORMING OF
THE WHOLE NERVOUS SYSTEM,
REQUIRING (INDISCERNIBLE) OF
A
VARIETY OF GENES. WE OFTEN
SAY
THERE IS A SINGLE MASTER
REGULATOR TO CONTROL AXON
REGENERATION WHETHER YOU
PREPARE
YOURSELF FOR NOT.
---
TAKING A MOLECULAR GENETICIST
APPROACH, THIS IS
CATEGORIZING
THE KEY GENES, EXPRESSING
THOSE
GENE MANIPULATING GENE
FUNCTION
AND ENABLE IMAGING, AND
GENERALLY
WE DIVIDE THE AXON INJURY
RESPONSE INTO THREE STAGES.
THE VERY IMMEDIATE STAGES A
CALCIUM TRANSIENT WHICH THEN
IS
FOLLOWED BY THE INITIATION
PHASE
OF REGROWTH, MEMBRANE REPAIR,
REORGANIZATION FOLLOWING THE
EXTENSION PHASE WHERE IT CAN
GROW
MORE OR LESS IN WHAT WE FIND
IS
OUR FOCUS TODAY MOSTLY IS ON
THE
DLK-KINASE.
AND A BIT ABOUT THE PROTEIN-
FINDING, PHASE SEPARATION AND
LATER I WILL TALK ABOUT
TRANSLATING CELF FUNDING INTO
MAMMALS AND COME BACK TO --
INVOLVING REGULATION AND IS
IN
THE LATEST -- ELONGATION OF
THE
DEVELOPMENTAL GUIDANCE
MOLECULES
START COMING TO PLAY TO
MODULATE
THE GROWTH DIRECTION AND
GROWTH
EXTENT.
---
LET ME START WITH THIS
PROTEIN
CALLED THE TIAR-2, AN
RI-BINDING
FACTOR, EXTENDING IT WITH
THREE
BINDING DOMAINS.
IT'S NAMED AS A TIA BECAUSE
IT IS
A PROTEIN EXPRESSED, A T-CELL
AS
AN ANTIGEN.
AND WHAT CHARACTERIZES THIS
FAMILY IS BESIDES THE THREE
DOMAINS, IT HAS A PRION-LIKE
DOMAIN.
IF YOU YEARS AGO THERE WERE
REPORTS ABOUT
MUTATIONS IN THE HUMAN TIA
GENES
ACTUALLY LINK TO STRESS--
DYNAMICS AS WELL AS ALS
PATIENTS.
---
A FORMER POST-DOC
CHARACTERIZED A
LOT OF BINDING FACTORS, LOTS
OF
(INDISCERNIBLE) WITH MORE
EXTENDED GROWTH AFTER INJURY
(TIAR-2),
AND WE WILL NORMALIZE THIS
GROWTH, ANYTHING ABOVE ONE IT
SHOWS THAT LOSING TIAR-2
LEADS TO
MORE REGROWTH EXTENSION.
AND IT SHOWS TIAR-2 ACTING IN
THE
EARLY PHASE.
HE THEN DID TRANSGENIC RESCUE
BY
PUTTING TIA INTO THE NEURONS
WHICH FULLY RESCUE THE
ASCENDED
REGROWTH PHENOTYPE,
BUT IT DOES NOT HAPPEN IF YOU
ARE
PUTTING THE GENES INTO MUSCLE
CELLS AND ADDITIONALLY HE
PLAYS
THE HUMAN TIA INTO
(INDISCERNIBLE) WHICH ALI
FULLY
RESCUED THE TIA NON-MUTANT
PHENOTYPE.
---
AND WHEN HE INCREASED THE
EXPRESSION LEVEL OF TIAR-2,
HE
STARTED SEEING INHIBITION, A
FACT
THAT ALSO REDUCED AXON
REGROWTH.
SO THE TIAR PROTEIN BEHAVES
AS A
DOSAGE AND IS A FACTOR ON
REGROWTH.
AND IT IS ALSO EXHIBITING
PATTERNS THAT ARE ALSO
DEPENDENT
ON DOSAGE.
IN SOME CASES AND THE AXONS,
THERE IS A SINGLE NEURON
CALLED
THE PLM, WITH A HIGH
EXPRESSION
LEVEL WILL FORM GRANULES AND
AT
LOW EXPRESSION IT IS DIFFUSED
AND
THIS CAN BE QUANTITATED HERE.
THIS KIND OF A CONCENTRATION
DEPENDS ON THE GRANULE
FORMATION,
RIGHT AROUND THE TIME CAME
THIS
IDEA OF LIQUIED PROTEIN
PHASED
OPERATIONS THAT COULD
(INDISCERNIBLE) BEHAVIOR.
AND MATT PURIFIED THE TIAR-2
PROTEIN TO PERFORM THE LIQUID
DROPLET ASSAY, WHICH HAS
CROWDING
FACTOR WHICH INSTANTLY SAW
THERE
IS INFORMATION OF THE
DROPLETS,
AND THOSE DROPLETS ONE OF THE
BEHAVIORS IS THAT THEY HAVE
LIQUID BEHAVIOR.
WHEN HE FRACKED THEM AND THEY
RECOVER VERY RAPIDLY.
---
AND THIS TIAR-2 GRANULES, IN
SUB-CULTURES THE TIAR PROTEIN
IS
BEEN CONSIDERED A CORE
COMPONENT
OF STRESS GRANULES INDUCED BY
STRESS BUT IN C ELEGANS AXONS
WE
DID AN EXTENSIVE STUDY WHERE
OTHER GRANULE MANUFACTURERS
AND
SYNOPTIC- PROTEINS, EXCEPT
THE
TIAR-2 ITSELF, GENERALLY
THERE IS
LITTLE COLOCALIZATION,
INDICATING THAT THE TIAR-2
PROTEIN IS RATHER
HOMOGENEOUS,
VERY DYNAMIC.
---
AND WE SEE THIS DYNAMIC
ASPECT IN
THE SLIDE IMAGING.
THAT IS WHERE YOU SEE THE
TIAR-2
GRANULES, BASICALLY COMING IN
FUSED AND SPLIT, BUT THEY
ACTUALLY NO LONG-RANGE
TRANSPORT.
---
AND ALSO RESPONDING TO INJURY
THIS IS SPLIT AND MERGED AS
SHOWN
HERE AND PREINJURY THERE IS
ONE
CLUSTER AND THEN AFTER INJURY
THIS TRIGGER SOMETIMES FEWER,
SOMETIMES MORE.
BUT THIS IS A VERY TREND IN
EVENTS. MATT DECIDED TO
ADDRESS
THE MECHANISM OF WHAT DRIVES
THIS
TIAR-2 BEHAVIOR AND FOR THIS,
THIS BASICALLY SUMMARIZED HIS
TWO-YEARS' WORK, EXPRESSING
GAP
TALK, TIAR-2 INVIVO
CONCENTRATION
IN A NICELY CONTROLLED WAY,
AND
TAKING EACH DOMAINS IT
PURIFIED
THE PROTEINS AND
(INDISCERNIBLE)
DROPLET HAVEN'S AS WELL AS IN
VIVO WHETHER IT FORMS
GRANULES
ARE NOT,
AND IT CAN RESCUE AND
COMPLEMENT
AXON REGENERATION PHENOTYPE.
AND THE SNAPSHOT IS THAT THE
FULL
LENS TIAR-2 FORMS GRANULES
AND
RESCUES THE ENHANCED AXON
REGROWTH OF TIAR-2 GROWTH.
AND WE DELETED ALL THE RM
DOMAINS, AXONS STILL FORMED
IN
THE ACTIVITY OF RESCUING THE
MUTANTS STILL THERE.
BUT WHEN HE PERTURBED THE --
LIKE
DOMAIN, EVEN A SMALL DEMAND
WHICH
ABOLISHED THE AXON GRANULE
SO
THERE IS A SMALL DOMAIN FOR
THE
NUCLEUS GRANULES PROVIDE THE
TIAR-2 FUNCTION.
AND I'M GOING INTO ADDITIONAL
DETAILS.
HE WAS ABLE TO DEFY BOTH A
PHOSPHORYLATION EVENT IN THAT
SMALL DOMAIN, RESPONSE TO
TRIGGER
OPERATIONS OR PICK THEM UP
WITH
THIS MODEL THAT IS IN AXONS,
TIAR-2 PROTEINS ARE ALWAYS
THERE
AND THEY UNDERGO A VERY
DYNAMIC
CHANGE.
(INDISCERNIBLE).
---
THIS TEMPORAL GRANULE
FORMATION
IS A STAGE SAMPLING THE
INJURY
SIGNAL AND SPREADING THE
SIGNAL
INTO THE ENTIRE AXON.
---
THIS STUDY WAS ABOUT THE SAME
TIME, NICELY SYNERGIZE WITH
JEFF
-- WORK, USING MOUSE SCIATIC
NERVE FOR THE IDENTIFIED A
BINDING FACTOR OF TIA
PROTEIN,
FORMING GRANULES AND IN A
PHOSPHORYLATION- DEPENDENT
MANNER.
UNDER THIS MECHANISM FROM C
ELEGANS TO MAMMALS AND HUMANS
AS
WELL.
---
SO THIS IS HOW WE WERE
DISSECTING
THE PROTEIN OF TIAR-2,
AND THIS IS GOING TO MY
FAVORITE
MOLECULE, THE DLK-1, NAMED
BECAUSE IT IS A MAPS 3
KINASE,
NOT ENTIRELY ACCURATE IN THE
SENSE THAT IS IN
(INDISCERNIBLE),
CHARACTERIZED BY TWO SUPER
DOMAINS ONE CALLED MAP3K12,
ONE
MAP3K13, THE 13 IS THE
(INDISCERNIBLE) KINASE.
THEY HAVE --
C ELEGANS HAS A SIMPLE NAME
CALL
THE DLK-1.
AND APART FROM THIS
CONSERVATION,
ALL THESE KINASES ARE
SUBJECTED
TO (INDISCERNIBLE) REGULATED
LIPID MODIFICATION.
---
WE STUDIED THE DLK, LONG
BEFORE
WE ESTABLISHED LASER EXALTOMY
ASSAY.
AND WE ESTABLISH THIS, AS
PART OF
THE EARLY INTEREST IN MY LAB,
HOW
DO WE FORM SYNAPSES?
WE USED THE -- LABELED GAP TO
MARK THE SYNAPTIC TERMINAL,
LOOKING FOR MUTANTS
DISRUPTING
THIS VERY NICE SYNOPTIC
PUNCTURE,
AND THIS LED TO A GENE CALLED
RPM-1 REGULATOR PRESYNAPTIC
MORPHOLOGY ONE,
IN THIS CLUSTER BECOME VERY
IRREGULAR COMPARED TO WILD
TYPE
NORMAL SHAPED
(INDISCERNIBLE),
AND THE ACTIVE ZONE PROTEIN
CALLED LIPRIN.
THIS ORGANIZED SYNOPTIC
CLUSTER
IN -- MUTANTS HAVE A LARGE
SPREAD
OF VESICOSE (INDISCERNIBLE).
AND IT TURNS OUT THAT THIS
PROTEIN -- FEELS LIKE MY
VOICE IS
NOT TRANSMITTING -- SO IT
TURNS
OUT THAT THE RPM-1 PROTEIN
IS
PART OF THE FAMILY CALLED PHR.
AND IT BUILDS A PROTEIN
CALLED
"HIGH WIRE."
THESE LARGE PROTEINS, CLOSE
TO
4000 IMMUNIZES (PHONETIC)
MORE OR
LESS
THEY ALL COME FROM THE WORK
OF
CORY GOODMAN, (INDISCERNIBLE)
--
ALL COME TOGETHER TO FORM
GENETICS AND MOLECULARIZED
APPROACHES SHOWING THAT
EVERYONE
PLACE IMPORTANT ROLES IN
DIFFERENT STAGES OF AXON
TERMINATION AND GUIDANCE,
SETTING
UP SYNAPSE STABILIZATION.
---
A COMMON FEATURE OF THIS PHR
PROTEIN IS THAT THIS SUGGESTS
IT
IS ACTUALLY AN EASERUBIC
(PHONETIC) LIGASE.
IT ACTS AS A SYNOPSIS.
WHAT WOULD BE ITS SUBSTRATE
AT
THE SYNAPSES?
FOR THIS MY LAB TOOK A
GENETIC
APPROACH,
LOOKING FOR SUPPRESSORS OF
RPM
SYNAPTIC PHENOTYPES.
IF THE (INDISCERNIBLE) IS NOT
THERE SOME PROTEIN IS UP
REGULATED,
THEN YOU CAN KNOCK IT DOWN
AND IT
COULD RESTORE THE SIGNALING
HOMEOSTASIS AND GETTING THE
SUPPRESSOR MUTATION.
THIS TURNED OUT TO BE A VERY
EFFECTIVE SUPPRESSIVE
MUTATION
AND WE IDENTIFIED
(INDISCERNIBLE)
AND DLK-1 KINASE AS WELL AS
THE
DOWNSTREAM KINASE AND FINALLY
A
TRANSCRIPTION FACTOR OF THE
LZ
DOMAIN TRANSCRIPTION FACTOR.
---
WE FURTHER SHOWED THAT THE
DLK
KINASE ITSELF IS A SUBSTRATE
OF
(INDISCERNIBLE) LIGASE.
AND THIS IS VERY LOW IN
ABUNDANCE.
YOU SEE AN ABUNDANCE
INCREASED IF
YOU REMOVE IT.
---
ALL OF THESE ARE BEAUTIFUL
GENETICS AND WE ENJOYED IT
VERY
MUCH BUT THEN THERE IS THE
QUESTION COMING IN.
IT APPEARS THAT DURING
DEVELOPMENT IN THE INITIAL
FORMATION OF SYNOPSIS THAT
DLK
KINASE NEEDS TO BE RAPIDLY
TURNED
OVER TO MAKE SURE THE
SYNAPSES
FORM PROPERLY AND LOSS OF
FUNCTION OF DLK IN ANY OF ITS
DOWNSTREAM TARGETS IS NOT
ESSENTIAL, AND THAT IS HOW WE
CAN
FIND THEM AS GENETIC
SUPPRESSOR
STRENGTH. THIS
RAISES THE QUESTION WHAT IS
THE
IMPORTANT FUNCTION OF THE
GENES?
IT SEEMS THAT IT'S IMPORTANT
IS
DEGRADED ACTIVELY.
UNTIL HE MADE THE CONNECTION
WHEN
WE WERE DOING THE LASER
EXOLTOMY
SCREEN AND REDISCOVER THE
DLK,
AND IT IS AWFULLY ESSENTIAL
TO
INITIATE THE INJURY INDUCED
REGROWTH AS YOU SEE HERE
COMPARED
TO WELL-TYPE. (INDISCERNIBLE)
AND
LOSS OF DLK DON'T FORM, AND
AXONS
STOP GROWING.
IF WE ELEVATE THE DLK, IT
INCREASE THE REGROWTH
COMPLETELY
DEPENDENT ON ITS TARGET SUCH
AS
THIS TRANSCRIPTION FACTOR.
BY ITSELF IT DID NOT
REGENERATE,
AND ALSO IT BLOCKS THE
ENHANCED
DLK OVEREXPRESSION EFFECT.
---
BESIDES TRIGGERING THIS
DEVELOPMENTAL SIGNALING
CASCADE,
DLK ALSO PROMOTE INJURY
INDUCED
MICROTUBULE DYNAMICS. YOU
RECALL
THAT WHEN WE USE BINDING
FACTORS
WE OBSERVED THERE IS INJURY
INDUCED EBP, AND SUSTAINED
EBP
GROWTH AND -- BOTH ARE
INDUCED
FEWER -- GETS INDUCED.
SUSTAINED GROWTH DOES NOT
HAPPEN.
COMBINED WITH OTHER GENES WE
CAN
SHOW PART OF THIS IS DUE TO
DISRUPTIONS IN
POST-TRANSLATION
MODIFICATIONS SUCH AS
TARASINATED
TUBULINGS (PHONETIC).
---
THERE IS A LOT OF INTEREST AT
THIS STAGE LINKING THIS DLK,
WORKING ALSO ON DLK-1 AND --
--
WORK ON NUTRACELL DLK.
THE - ACTION HAS TWO
HOMOLOGUES,
BOTH EXPRESSING IN THE
NERVOUS
SYSTEM AND CLONED FROM
(INDISCERNIBLE) -- BOTH
KINASE
CAN ACT TO -- SIGNALING.
THERE ARE MULTIPLE DLK MICE,
GENERALLY DIE PERINATALLY.
IF THEY ARE DELETED IN
ADULTS,
AND THIS IS WHERE YOUR
SCIENCE
DEPARTMENTS -- THOSE DLK MICE
ARE
PERFECTLY FUNCTIONING ADULTS.
---
THERE IS A STUDY -- PERFECTLY
VIABLE, NO DETECTABLE DEFECTS.
BUT IN THE LAST 10 YEARS,
INDIA
FROM USING MAMMALIAN
AXON-REGENERATION RESEARCHERS
PARTICULARLY FROM OPTIC NERVE
INJURIES,
FROM A GENETIC GROUP AS WELL
AS
THE JOHNS HOPKINS GROUP,
AND SOME PEOPLE USING THE
PERIPHERY NERVE INJURY --
HAVE
ALL SHOWN THAT THE DLK KINASE
IS
IMPORTANT FOR OPTIC NERVE
INJURY
INDUCED AXON SPROUTING; OPTIC
NERVE -- SURVIVAL AS WELL AS
REGENERATION EFFECT IN MY LAB
IN
COLLABORATION WITH -- GROUP
AT
UCSD DECIDED TO FOCUS ON DLK
KINASE SHOWING THAT IT HAS
STRONGER ROLE IN ASTRO CIZ3
(PHONETIC) -- INDUCED BY
INJURY
INVOLVING -- AND AT NIH HAVE
ALSO
IMPLICATED DLK'S ROLE IN HER
CAREER AND HER EARLY WORK
(INDISCERNIBLE) THE DLK
KINASE IS
PROTECTIVE IN ANIMAL MODELS
FOR
NEURODEGENERATIVE DISEASES
SUCH
AS ALZHEIMER'S AND ALS.
---
IN RECENT YEARS, THROUGH
COLLABORATION WITH -- GROUP,
WE
ADDRESS THE FACT THAT DOES
THE
DLK AND LZK HAVE ANY ROLE IN
SPINAL CORD INJURY?
THERE ARE EXTENSIVE MOUSE
GENETICS; WE WILL HAVE TO USE
THE
P10 AS A BACKGROUND.
IN THE SPINAL CORD WHICH IS A
CENTRAL NERVOUS SYSTEM, AXONS
DON'T REGROW UNLESS YOU ARE
--
AND STARTS SPROUTING, THAT
WAS
QUITE A LOT OF WORK.
IF THIS FIGURE IS TOO MUCH TO
LOOK, THE IMPORTANT THING IS
THAT
THIS IS THE CONTROL,
ESSENTIALLY
FOLLOWING DORSAL HEMI
TRANSECTION
(PHONETIC),
AND NO SPROUTING -- -- BUT
REMOVING DLK AND LZK
ESSENTIALLY
THERE IS LITTLE SPROUTING TO
BLOCK THE P10 EFFECT.
INDIVIDUALLY DLK AND LZK DID
NOT
HAVE THIS STRONG EFFECT.
SO THEY ARE BLOCKING SPINAL
CORD
AXON REGENERATION AND INDUCED
(INDISCERNIBLE) DELETION.
---
THIS IS ALL GOOD TO SUPPORT
THAT
THE WHOLE -- OF THE DLK
KINASE
ALONG WITH HIS SISTER KINASE
ARE
IMPORTANT FOR INJURY RESPONSE
FROM C ELEGANS TO MAMMALS.
AT THE SAME TIME YOU HAVE TO
THINK ABOUT,
IT IS NOT JUST TO BLOCK
THINGS,
YOU HAVE TO THINK ABOUT
ACTIVE
DLK SO YOU CAN PROMOTE AXONS
TO
REPAIR, REGROW AND DO
SOMETHING
BETTER. IN THIS CASE IT WAS
INTERESTING TO MENTION THESE
TWO
STUDIES.
ONE THIS WORK FROM THE UCLA
GROUP
SHOWING THAT IN THE
PARTICULAR
CONDITION, THE STROKE MODEL,
INHIBITING CCR5, CYTOKINE
RECEPTOR, IT HELPED THE MOUSE
TO
RECOVER FROM THE STROKE DUE
TO
THE FACT THAT THEY WERE ABLE
TO
SHOW THAT BLOCKING CCR5
FOLLOWING
THE STROKE AND DLK IS
UPREGULATED, TRIGGERING CROSS
SIGNALING WHICH TRIGGERS
(INDISCERNIBLE), AND SOME
PATIENTS WHO HAVE RECEIVED
CCR5
INHIBITORS ALSO RECOVER WELL.
IN THIS CCR5 STROKE MODEL
ACTIVE
DLK HELD THE MOTOR AXON
PLASTICITY TO HELP RECOVER
FROM
STROKE.
AND THIS ADDRESSES USING
HUMAN
INDUCED STEM CELLS,
ADDRESSING
HOW HUMAN INDUCED, HUMAN CELL
INDUCED NEURONS ARE
RESPONDING TO
APOE FACTORS WHICH IS A MAJOR
TRIGGER FOR ALZHEIMER'S AND
BY
APPLYING THE APOE4, THE CELLS
RESPOND POTENTLY TO
UPREGULATED
DLK KINASE AND THERE IS A
TRANSCRIPTION UP REGULATION
OF
APP.
IN OTHER WORDS -- IS UP
REGULATING DLK, AND
DEPENDING ON
WHAT SYSTEM YOU ARE SETTING
UP IT
COULD BE GOOD PROMOTING AXON
SPROUTING -- AND PROMOTING
APP
PRODUCTION WHICH IS
CONSISTENT
WITH CLARIS'S WORK,
INHIBITING
DLK CAN REDUCE NEURO-
REGENERATIVE PHENOTYPES.
--- WE ARE EXAMINING MICE AND
(INDISCERNIBLE) EXPRESSION
FOCUSING ON THE CEREBELLUM,
AND WE HAVE OUR COLLEAGUES TO
HELP US LEARN THE MOUSE
ANATOMY.
SUFFICE IT TO SAY THAT AFTER
THE
CONDITIONAL OUTCOME OF DLK
AND
LZK, BASICALLY THE CEREBELLUM
DEVELOPED QUITE NORMAL.
NO DEFECTS WE CAN DETECT.
YUNBO AND ERIN REGENERATED
THE
TRANSGENIC DLK, ALLOWING US
TO
MANIPULATE THE CELL TYPES AND
WE
WOULD CROSS THEM WITH -- IN
THIS
CASE DLK IS UPREGULATED TWO-
TO
FOUR-FOLD, UP REGULATING
SIGNALING,
AND MOST OF THE NEURONS
BASICALLY
DIE AND BY P21 MICE ALSO DIE
PERHAPS DUE TO ITS EFFECT IN
OTHER NEURONS.
---
IN CONTRAST, WE MADE THE SAME
KIND OF MICE, THIS TIME
INDUCIBLE
OVEREXPRESSING LZK, AND THOSE
MICE CAN LIVE HAPPILY AFTER A
YEAR -- (INDISCERNIBLE) --
LIVE
UP TO FOUR MONTHS, 40-60%
DEATHS.
AND LZK OVEREXPRESSION ALSO
INDUCED JUNK SIGNALING AND
THAT
IS INDUCED IN THE CUSP SPACE.
WE STARTED ASKING THE
QUESTION,
HOW CAN THESE TWO KINASES
SEEM TO
BEHAVE THE SAME?
WHY DID THEY APPEAR TO HAVE
DIFFERENT POTENCIES IN NEURON
SURVIVAL?
A LOT OF THIS IS GENERIC
THING.
TRIPLE KINASE WILL ACTIVATE
THE
DOUBLE KINASE AND GO THROUGH
THE
JUNK SIGNALING TO STRESS
KINASE.
IN THINKING ABOUT THE TWO
KINASE
DIFFERENCES, WE READ THIS
PAPER
WHICH ACTUALLY STUDIED T CELL
ACTIVATION. IN THIS PROCESS
JUNK
SIGNALING IS WIDESPREAD, AND
ONE
OF THE JUNK SIGNALING IS
INDUCED
BY MANY GENES INVOLVED IN T
CELL
DIFFERENTIATION.
THIS GROUP IDENTIFIED THE
MECHANISM TO SHOW THAT
THE JUNK UPSTREAM KINASE,
MKK7, DURING CHELSEA
(CORRECTION)
DURING T-CELL ACTIVATION.
(INDISCERNIBLE).
THE PRESENCE OF CELF2
SPLICING
FACTOR WILL INCLUDE THIS
ALTERNATIVE AXON
WILL HAVE THIS DOUBLE KINASE
AND IT WILL RESULT IN A LESS
ACTIVE MKK7.
---
SO WHAT WE HAPPENED TO
REALIZE IS
THAT THERE IS A CELF
HOMOLOGOUS
2, IN BINDING FACTORS WITH
THE 3
RM DOMAINS, MOSTLY NUCLEAR,
NAMED
(INDISCERNIBLE) BINDING
FACTOR.
AND THE WORK OF MY FORMER
POST
DOC LIZHEN CHEN WHO IS NOW
PROFESSOR AT -- SHE OBSERVED
LOSING UNC-75, AXONS DON'T
GROW
MUCH,
NOT AS SEVERELY IMPAIRED AS A
DLK
LOSS OF FUNCTION BUT IT WILL
REDUCE THE REGROWTH.
SHE ALSO DECIDED TO VENTURE
INTO
-- FIELD AND GOT THE CELL TO
(INDISCERNIBLE) AND LOOKING
AT
THE SCIATIC NERVE
REGENERATION.
SHE BASICALLY DELETED THE
CELF2
FROM DRG AXONS MARKED IN RED.
THESE REGENERATING AXONS,
FOLLOWING THE CRASH AND THE
SCIATIC NERVE IS MARKED BY A
CG
10, AND FOLLOWING THIS CRASH,
THIS WOULD REGENERATE QUITE
WELL,
LOSING (INDISCERNIBLE) AND
REDUCING RATE GROWTH.
LOOKING FOR SPLICING TARGETS
BEGINNING TO IDENTIFY A
SERIES OF
TARGETS WHICH INCLUDED
SYNAPTIC
TRANSMISSION GENES ACROSS.
---
NOW WE CAN START PUTTING
TOGETHER
THE C ELEGANS AND THE MOUSE
WORK
TO ASK THE QUESTION COULD
CELF2
INFLUENCE THE DLK AND LZK
EFFECT
THROUGH ALTERNATIVE SPLICING
OF
MKK7?
FOR THIS WE MADE EXTENSIVE
GENETIC MOUSE -- COMBINATIONS.
AND ADDITIONAL DELETING CELL
IN
THE DLK OVEREXPRESSION MICE,
AND
ASKING TODAY BLOCK THE
CONTINUING
CELL DEATHS.
THERE IS NO EFFECT WHATSOEVER.
BUT WITH LZK OVEREXPRESSION
WE
SEE A VERY SIGNIFICANT
SUPPRESSION OF LZK-INDUCED
PURKINJE CELL DEATHS.
THOSE ANIMALS LIVE MUCH
LONGER
AND HAPPIER.
---
THROUGH EXAMINING SIGNALS
FROM C
ELEGANS TO MAMMALS, WE ARE
FILLING IN ONE PART OF THE
KNOWLEDGE THAT DLK PROBABLY
ACTING THROUGH A DIFFERENT --
CALLED MKK4 AND
(INDISCERNIBLE)
WHERE LZK ACCESS THROUGH MKK7
AND
TRIGGERS A SLOW JUNK
SIGNALING
LEADING TO (INDISCERNIBLE)
AND
BOTH KINASES EVEN THOUGH THEY
BEHAVE THE SAME IN NEURONS
THE
SAME TO HAVE NEURON-TYPE
SPECIFICITY DEPENDING ON THE
DOWNSTREAM NEURON.
---
SO THIS IS ALL PUBLISHED
WORK,
BUT YOU STILL HAVE NOT ANSWER
THE
QUESTION EVEN IN C ELEGANS,
HOW
IS THE DLK LEVEL UPREGULATED?
SO I'M GOING TO ACTIVELY WORK
IN
C ELEGANS.
THIS IS A WORK FROM A
GRADUATE
STUDENT AND POSTDOC -- WHAT
THEY
DID IS THEY TOOK ADVANTAGE OF
GENETIC TAGGING IN DLK AND
DECIDED TO LOOK FOR WHAT
COULD BE
UPREGULATED.
SO WHAT WE ARE SHOWING HERE
IS
THE C ELEGANS WORM AND THE --
IS
HERE WITH LESS SOMA AND THE
--
CONNECTED HERE AND WOULD WE
SEE
ENDOGENOUS DLK, I CAN SEE ON
SCREEN, I DON'T KNOW IF IT
WILL
SHOW UP, THEN THEY FEED THE
WORM
WITH -- AND ISOLATED MUTANTS
THAT
WILL INCREASE THE DLK LEVEL,
LIKE
IN TRANSGENIC MICE, BUT WE
ARE
LOOKING FOR MUTATION.
SURE ENOUGH WE GOT A POSITIVE
CONTROL BECAUSE DLK NOT ONLY
INHIBITED DEGRADED THE LIGASE
(INDISCERNIBLE) -- ALSO
IDENTIFIED A TUBULIN,
UNEXPECTED AND IT IS CALLED
THE
BEN-1 AND THE C ELEGANS BEN-1
IS
QUITE WELL STUDIED,
STUDY FOR SOME YEARS FROM --
GROUP.
IT IS A NEURON SPECIFIC B-
TUBULIN ISOLATED BECAUSE
WORMS
ARE SENSITIVE TO THIS CALLED
BENOMYL, AND EVENTUALLY TO
BECOME
STERILE AND THEY DIE.
LOSS OF FUNCTION OF BEN-1 IS
RESISTANT TO BENOMYL, AND
THEN
THEY GROW PERFECTLY FINE
WHEREAS
OUR MUTATION IS THIS ONE IN
THE
TUBULIN. TUBULIN'S ARE GTPA,
AND
THEY ARE PRETTY ACTIVE AND
THEY
FOLD EXTENSIVELY AND THERE IS
THIS LOOP CALLED THE T7 LOOP,
IN
THE ALPHA-BETA TUBLING
INTERFACE
IN OUR MUTATIONS AFFECTING
THIS
LOOP, IT BEHAVED --
(INDISCERNIBLE)-- BECAUSE IT
IS
HYPERSENSITIVE TO BENOMYL.
THE GENE IS HARD TO REMEMBER
BUT
EASY TO MAKE FOR THOSE
FAMILIAR
WITH THE VERTEBRAE TUBULI.
THERE HAVE BEEN MANY
MUTATIONS,
DISRUPTING HUMAN TUBB3
RESULTING
IN DISORDERS.
BASICALLY THERE IS A LACK OF
MAMMALIAN TUBB3, BECAUSE IT
ALSO
CONVERS SENSITIVITY TO
BENOMYL.
---
THIS MUTATION THAT I SHOWED
YOU
IS ISOLATED BECAUSE IT
ISOLATED
THE DLK LEVEL, AND NOT ONLY
IT UP
REGULATES BUT IT ACTIVATES
ITS
DOWNSTREAM SIGNALING.
DOWNSTREAM OF THE DLK IS A
PRESCRIPTION FACTOR CEBP-1.
IT UBIQUITOUSLY IS EXPRESSING
IN
ALL TISSUES, VERY LOW IN THE
NEURONS IN THE HEAD AND IN
MOST
PLACES.
BUT IN THE MUTANT YOU CAN SEE
IT'S EXPRESSION LEVELS
UPREGULATED IN MOST NEURONS,
NOT
IN NON-NEURAL TISSUES.
AND THIS MUTATION IS ACTING
IN
PARALLEL TO UP REGULATE LOSS
OF
FUNCTION WHERE THE DUCKTAPE
WORM,
WHICH MOVES WELL,
THERE IS A LOSS OF FUNCTION,
ALSO
PRETTY MUCH NORMAL BUT DOUBLE
MUTANTS ARE PARALYZED.
AND WHEN WE LOOK AT THE
SYNOPSIS,
YOU CAN SEE THE SYNOPTIC
PUNCTURE
IN THE WILD TYPE,
VERY DISCREET.
THE BEN-1 FUNCTION IS ALSO
DISCRETE,
DISRUPTING THE SHAPE OF THE
SYNOPSIS AND THE DOUBLE
MUTANTS
LOOSE BASICALLY MOST SYNAPSES
AND
MOST ARE PARALYZED.
SO THE BEN-1 FUNCTIONS ACT IN
A
PARALLEL PATHWAY, IT IS A
TUBULIN, AND WE WERE USING
THE
EBB -BINDING ASSAY.
IN THIS PARTICULAR FUNCTION
ACTUALLY, THE MICROTUBULE
DYNAMICS ARE ONLY SUBTLY
ALTERED,
NOT DRAMATIC.
THIS FUNCTION CHANGE THE
MICROTUBULE DYNAMICS AND IT
ACTIVATES THE DLK MODERATELY.
IT HAS A PROTECTIVE ROLE IN
SYNOPSIS IN MULTI NEURAL
FUNCTION.
THIS SHOWS LOOKING AT THE
SYNAPTIC PUNCTURE, AND
LOOKING AT
THE -- FUNCTION AND DLK LOSS
FUNCTION, ALL LOOK FAIRLY
SIMILAR
BUT THE REASON WE SAY
ACTIVATED
DLK FUNCTION PROTECTS
SYNAPSES IS
WE TAKE OUT THE DLK IN THE
BEN-1
IN THE FUNCTIONAL MUTANT AND
THE
SYNOPSIS GETS SEVERELY
DISRUPTED.
THIS IS OPPOSITE BY SAYING
THAT
WHEN WE DID -- LOSS OF
FUNCTION,
WHEN WE TOOK OUT DLK, IT
RESTORED
FUNCTIONS BUT HERE WE TOOK
OUT
THE DLK AND MADE THE SYNAPSES
WORSE, AND THE MOTOR BEHAVIOR
WORSE.
THIS IS A MODERATE INCREASE
OF
DLK LEVEL.
---
WHEN WE TREAT THE ANIMALS
WITH
BENOMYL, IT DEPOLARIZES MANY
TUBULINS.
IT IS SEVERELY ALTERED BOTH
IN
THE NUMBER OF TRACKS AS WELL
AS
SHORT NUMBERS OF
(INDISCERNIBLE).
---
IN THIS CASE WHAT WE SEE IS
THAT
BENOMYL TREATMENT DEPORALIZES
THE
MAJORITY OF THE BUCKET
TUBULES.
THIS IS -- THE ANIMALS WERE
PARALYZED AND DLK BLOCKS THIS
EFFECT.
IN THE SEVERE CASE, DLK IS
BASICALLY BLOCKING THE
MICROTUBULE DISRUPTION AND
INDUCED A SYNAPTIC DISRUPTION
AND
IN THIS CASE, WE SEE A DOSAGE
EFFECT.
MODEST DISRUPTION OF
MICROTUBULES
-- THIS IS MY LAST SLIDE --
IN
THE STEADY-STATE DLK
SIGNALING IS
MODERATELY ACTIVITY TO CREATE
A
TIGHTLY REGULATED -- LIGASE
OF
THE SIGNALING CONSTANTLY IS
UNDER
CONTROL.
WITH THE -- FUNCTION THERE IS
A
SLIGHT CHANGE IN MICROTUBULE
DYNAMICS WHICH UP REGULATES
THIS
SLIGHTLY AND IT ALTERS THIS.
AND THE PURPOSE OF OPERATING
THE
SIGNALING IS THE CHANGES OF
MICROTUBULE DYNAMICS TO KEEP
THE
SYNAPSES BACK TO NORMAL IN
THIS
CASE DLK IS UPREGULATED, AND
IN
THIS CASE IT EXCEEDED THE
FIRST
THRESHOLD AND SYNOPSES BECOME
TOTALLY UNSTABLE AND NEURONS
NO
LONGER FUNCTION NORMALLY.
SO THAT LEAVES ME WITH MY
WORKING
MODEL FROM STARTING FROM ONE
SCREEN TO ANOTHER SCREEN
TESTING
OUR HYPOTHESES USING MOUSE
MODELS.
WE LIKE TO THINK THAT THIS
STRESS
KINASE DLK IS ACTIVATION,
TIGHTLY
COUPLED TO MICROTUBULE
DYNAMICS,
NEURON SPECIFIC TO AN ISO
FORM.
AND HOW THIS TIGHT COUPLING
IS
ACTUALLY MECHANISTICALLY, AT
WHAT
LEVEL IS A QUESITON MARK THAT
WE
DO NOT KNOW.
IT WILL CREATE A CONTEXT
-DEPENDENT OUTCOME WHETHER
NEURONS WILL SURVIVE,
FORM NORMAL SYNOPSES,
REGENERATING OR DEGENERATING.
WE HAVE A LOT MORE WORK TO DO
BUT
I WANT TO END THE TALK
SHOWING
THE PEOPLE IN MY LAB.
AND THE FIRST OUTINGS LAST
YEAR
AFTER THE PANDEMIC AND THE
KEY
PEOPLE
WHO DID THE WORK ARE ERIN,
RICHIE, -- MY COLLABORATOR
AT
UCSD -- AND THE C ELEGANS
AXON
AND COLLABORATION IN SPINAL
CORD
INJURY, AND THEY ALL
CONTRIBUTED
TO EACH OF THE STORIES THAT I
TALKED TO YOU ABOUT. THANK
YOU TO
NIH FOR A VERY LONG SUSTAIN
SUPPORT, AND IT HELP ME TO
SET UP
THE MOUSE WORK AND JUNOR
SEAU, A
HERO IN THE FOOTBALL ERA FOR
WHICH WE HAVE THE HONOR TO BE
THE
CHAIR AND THE REST OF THE
SUPPLIES.
THANK YOU FOR COMING.
>> [APPLAUSE]
>> ANYONE IS FREE TO USE THE
MICROPHONES TO ASK A
QUESTION.
I HAVE ONE THAT HAS COME IN
ONLINE.
A TWO-PART QUESTION.
THIS IS FROM -- A RESEARCHER
HERE.
THANK YOU SO MUCH FOR SHARING
THIS AWESOME WORK, VERY
INTERESTING.
YOU FOCUSED ON INJURY INDUCED
REGENERATION IN AXONS.
IS THE SAME MECHANISM
EMPLOYED
FOR DAMAGED DENDRITES?
PART TWO,
DOES THE INJURY INDUCED
REGENERATION FULLY RESTORE
FUNCTIONS OF THE DAMAGED AXON
TO
THE STATE BEFORE THE INJURY?
AXONS CARRY MANY FUNCTIONAL
UNITS, FOR INSTANCE AXON
INITIATED SEGMENT- AND
(INDISCERNIBLE) AND ACQUIRED
SYNOPTIC STRENGTH.
THANK YOU FOR ANSWERING THE
QUESTION.
>> DR. JIN:
THANK YOU FOR THE QUESTION.
THE FIRST IS EASY TO ANSWER.
I DID FOCUS IN ALL OF MY WORK
ON
AXON REGENERATION BUT ONE
THING
TO KEEP IN MIND IS THAT C
ELEGANS
ARE SIMPLE AXONS, AND SOME OF
THEM ARE MIXED POLARITY.
IN OUR LAB, WE WERE WORKING
WITH
THE C ELEGANS TESTING
MULTIPLE
TYPE OF NEURIDES, AND PURITY
DENDRITE AND GENERALLY C
ELEGANS
DENDRITES DO NOT GENERATE NOT
BECAUSE THE DLK IS NOT THERE.
THEY DON'T REGENERATE.
I WILL TALK ABOUT AN OFFER --
THE
INTRA CEPHULA (PHONETIC)
(INDISCERNIBLE) --
OTHER PEOPLE'S WORK.
IN THAT SENSE I WILL SIMPLY
SAY
THAT BECAUSE C ELEGANS AXONS
HAVE
A UNIQUE ARCHITECTURE WE
FOCUS ON
AXON REGENERATION.
---
THE SECOND QUESTION, AXON
REGENERATION IS VERY COMPLEX,
I
TOTALLY AGREE.
AT THIS STAGE FROM THE C
ELEGANS
WORK, OUR GOAL IS TO LOOK FOR
GENES THAT WILL RESPOND TO
INJURY, AND IN THAT SENSE WE
HAVE
NOT EXPLORED INTO IN-DEPTH OF
DIFFERENT FORMS WHETHER THE
AXON
WILL SPROUT OR BRANCH AND
FORM
SYNOPSES IN ANY WAY BUT IN
COLLABORATION WITH -- LAB, WE
LOOKED INTO SPINAL CORD
INJURY
WHICH HAS WHEN THEY DO DORSAL
HEMI TRANSECTION, THE SPINAL
CORD
COULD HAVE A SPARED AXON AND
SPROUTING, AND THEY CAN ALSO
PULL
IN AN INJURED AXON ALSO
SPROUTING
AND WHAT -- GROUP HAS
OBSERVED
THAT BOTH EFFECTS ARE
DEPENDENT
ON DLK.
SO THERE ARE SINGLING EVENTS
THAT
SOMEHOW THE NEURON WILL SENSE
THE
INJURY PRESENT AND WILL
RESPONSE.
WE HAVE NOT SEEN THE
REFORMING
SYNOPSES BY MANIPULATIVE
SINGLE
GENETIC FACTORS,
SOMETIMES USING MULTIPLE
FACTORS
CAN MAKE THE INJURED AXONS
GROW
BETTER BUT THE SYNOPSES IS
NOT
FORMED PROPERLY.
---
IN C ELEGANS, SOME OF THE
WORK WE
KNOW IS THAT THEY CAN BE
DISCONNECTED AND HAVE A
CERTAIN
DEGRADED FUNCTION DEPENDING
ON
THE CIRCUITS, DEPENDING OF
THE
ULTIMATE SYNOPSES IS IN THE
(INDISCERNIBLE) MUSCLES.
>> THANK YOU VERY MUCH.
IT'S BEEN QUITE AN AMOUNT OF
INTERESTING STORIES.
MY QUESTION HAS TO DO WITH
THE
PREOWNED DOMAIN OF THE GRR
REQUIRED FOR BOTH FUNCTION
AND
DROPLET DISTRIBUTION.
YOU DESCRIBED THE
PHOSPHORYLATION
OF THAT DOMAINS WHICH IN MY
MIND
IS PRONE TO AGGREGATION.
AND SOMEBODY ELSE'S GROUP,
PHOSPHORYLATION ENHANCED THE
PARTITION.
ISN'T IT COUNTERINTUITIVE?
>> DR. JIN:
YEAH.
PHOSPHORYLATION, HOW IT IS
MODULATING AND SOMETIMES IT
COULD
BE TRIGGERING SIGNALS, THE
PHOSPHORYLATION ALSO CHANGES
THE
CHARGE ENVIRONMENT.
SO THE PHASE SEPARATION HAS A
LOT
TO DO WITH CROWDING, HOW YOU
GET
TO YOUR NEIGHBORS.
I HAVE SEEN SOMETIMES
REPORTING
THAT PHOSPHORYLATION PROMOTES
DROPLET FORMATION.
AND THE DROP TO SOLID-STATE.
A LOT OF THIS IS COMING,
EVENTUALLY DISCOVERING WHO IS
DROPLETS FORMING WITH.
>> I SEE.
>> DR. JIN:
WE HAVE NOT ACTUALLY IDENTIFY
THE
KINASE, EXCEPT WE HAVE
MUTATED
THE RESIDUES AND WE SEE
CHANGES
IN (INDISCERNIBLE).
>> THANK YOU.
>> CONCLUDING COMMENTS?
>> THANK YOU SO MUCH.
IT'S BEEN A PLEASURE TO SEE
ALL
OF THIS TOGETHER.
WE ALL HAVE BEEN READING YOUR
PAPERS, BUT SEEING HOW THEY
COME
TOGETHER IS QUITE
ENLIGHTENING.
AND I'M ALWAYS THRILLED TO
HEAR
YOUR STORIES.
AND I AM SURE MANY IN THE
AUDIENCE FEEL THE SAME.
THANK YOU.
>>DR. JIN:
THANK YOU VERY MUCH FOR YOUR
QUESTIONS.