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Giant Chromosomes and Deep Sequences: What the Frog Egg Tells us about RNA Transcription

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Air date: Wednesday, February 26, 2014, 3:00:00 PM
Time displayed is Eastern Time, Washington DC Local
Views: Total views: 319, (116 Live, 203 On-demand)
Category: WALS - Wednesday Afternoon Lectures
Runtime: 01:07:16
Description: Wednesday Afternoon Lecture Series

Dr. Joseph G. Gall (Carnegie Institution for Science) is the winner of the 2006 Lasker and described as the founder of modern cell biology, the inventor of in situ hybridization, and an early champion of women in science.

The eggs of frogs and salamanders contain exceptionally large chromosomes, known since the 19th century as "lampbrush" chromosomes because of their unusual fuzzy appearance under the microscope. The many "bristles" on these chromosomes are actually loops composed of one or a few actively transcribing genes. These genes synthesize RNA at rates much higher than in typical somatic cells, making it possible to study RNA synthesis in exquisite detail by immunofluorescent staining and in situ hybridization. The giant lampbrush chromosomes are contained in an equally giant nucleus, known as the germinal vesicle (GV). Because the GV has a diameter of up to a millimeter in some species, it can be removed manually from the egg under a dissecting microscope. In this way one can prepare absolutely pure nuclear and cytoplasmic fractions of the egg for molecular analysis. Deep sequencing of nuclear and cytoplasmic RNA confirms that the cytoplasm contains many species of messenger RNA, as expected. However, much of the nuclear RNA consists of sequences derived from the non-coding introns of genes. Some of these introns persist into the developing embryo and could be involved in gene regulatory processes.

For more information go to http://wals.od.nih.gov
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NLM Title: Giant chromosomes and deep sequences : what the frog egg tells us about RNA transcription / Dr. Joseph G. Gall.
Series: NIH Wednesday afternoon lecture
Author: Gall, Joseph G.
National Institutes of Health (U.S.),
Publisher:
Other Title(s): NIH Wednesday afternoon lecture
Abstract: (CIT): The eggs of frogs and salamanders contain exceptionally large chromosomes, known since the 19th century as "lampbrush" chromosomes because of their unusual fuzzy appearance under the microscope. The many "bristles" on these chromosomes are actually loops composed of one or a few actively transcribing genes. These genes synthesize RNA at rates much higher than in typical somatic cells, making it possible to study RNA synthesis in exquisite detail by immunofluorescent staining and in situ hybridization. The giant lampbrush chromosomes are contained in an equally giant nucleus, known as the germinal vesicle (GV). Because the GV has a diameter of up to a millimeter in some species, it can be removed manually from the egg under a dissecting microscope. In this way one can prepare absolutely pure nuclear and cytoplasmic fractions of the egg for molecular analysis. Deep sequencing of nuclear and cytoplasmic RNA confirms that the cytoplasm contains many species of messenger RNA, as expected. However, much of the nuclear RNA consists of sequences derived from the non-coding introns of genes. Some of these introns persist into the developing embryo and could be involved in gene regulatory processes.
Subjects: Cell Nucleus--genetics
Oocytes--metabolism
RNA--metabolism
Salamandridae--genetics
Xenopus laevis--genetics
Publication Types: Lectures
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NLM Classification: QY 60.A6
NLM ID: 101629948
CIT Live ID: 13724
Permanent link: https://videocast.nih.gov/launch.asp?18299