Analysis of period transcript structure and function within the Drosophila circadian oscillator /
The period (per) gene encodes a central component of the circadian clock in Drosophila melanogaster. It was reported eleven years ago that per has three types of transcripts (type A, type B and type C) that encode three different proteins. In the first part of this study, per was found to have onl...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=737708221&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The period (per) gene encodes a central component of the circadian clock in Drosophila melanogaster. It was reported eleven years ago that per has three types of transcripts (type A, type B and type C) that encode three different proteins. In the first part of this study, per was found to have only two transcripts, type A and type B', which differ by the presence of an alternative intron in their 3' untranslated regions (3'-UTR). Type A and type B' transcripts are found in different tissues with varying ratios, and the levels of these transcripts cycle both in fly heads and bodies with identical phases but different amplitudes. The alternative intron in 3'-UTR of per was found to affect the circadian period of locomotor activity rhythms. Circadian fluctuations in per MRNA and per protein (PER) constitute part of a feedback loop which is required for circadian pacemaker function. PER cycling is required for per RNA cycling, but the converse has not been tested. The feedback loop operates in many tissues but whether it operates autonomously in each tissue is unknown. In the second part of this study, transgenic flies which express wild type levels of per specifically in photoreceptors Rl-R6 were generated. Under both light:dark (LD) cycling and constant dark (DD) conditions, per protein (PER) abundance cycles in the absence of circadian cycling of per MRNA. These results show that per mRNA cycling is not required for PER cycling, and indicate that eye photoreceptors RI-R6 contain a tissue autonomous circadian oscillator. One of the transgenic strains generated in this project also expresses PER in eyes and lateral brain neurons (LNs), presumably due to an enhancer-trap. This strain restores locomotor activity rhythms without per MRNA cycling. This result indicates that per MRNA cycling is also not required for locomotor activity rhythms. |
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| Item Description: | Vita. "Major Subject: Biology". |
| Physical Description: | xii, 133 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 91-101 and page 131. |