Characterization of lin-42/period transcriptional regulation by the Ikaros/hunchback-family transcription factor ZTF-16 in Caenorhabditis elegans

The gene lin-42 is an ortholog of the mammalian period gene, a component of the circadian pathway that converts environmental stimuli into behavioral and physiological outputs over 24 hours. Mammalian period also regulates adult stem cell differentiation, although this function is poorly understood. The structure, function and expression of lin-42 are all similar to period. Therefore, we are studying lin-42 regulation and function during C. elegans larval development as a model for understanding period control of mammalian stem/progenitor cell development. Previous work has shown that ZTF-16 is a regulator of lin-42 transcription. The lin-42 locus encodes three isoforms, and we have characterized lin-42 isoform specific regulation by ZTF-16 through phenotypic assays and analysis of transcriptional reporter strains. Our data show that ZTF-16 regulates the cyclic expression of lin-42A and lin-42B during larval development. However, ztf-16 is not expressed during the adult stage and does not regulate lin-42C, which is expressed only in adults and may be responsible for the circadian functions of lin-42. We also show that ztf-16 reduction-of-function mutations phenocopy loss-of- function phenotypes of the lin-42A/B isoforms. Finally, we have found that deletion of a putative ZTF-16 transcription factor binding site within the lin-42BC promoter abolishes tissue-specific expression patterns. Together, these data indicate that ZTF-16 is required to regulate the expression of lin-42A/B during C. elegans development, and may do this by direct binding to the lin-42BC promoter. Our findings pave the way for testing the possible regulation of period expression by HIL-family transcription factors in mammalian tissues.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Biological Sciences

Department dc:contributor.department

Biological Sciences

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2013

Author dc:creator

• Meisel, Kacey Danielle

Chair dc:contributor.committeechair

• Banerjee, Diya

Committee members dc:contributor.committeemember

• Kuhn, Jeffrey R.
• Jensen, Roderick V.
• Eyestone, Willard H.

• lin-42
• period
• ZTF-16
• stem cell development
• C. elegans
• microbombardment
• transcriptional reporter

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:1131

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/23130