The C. elegans tbx-2 gene encodes a conserved member of the T-box transcription factor family essential for development of ABa-derived pharyngeal muscles. The tbx-2 promoter is active in pharyngeal precursors prior to formation ofthe pharyngeal primordium, as well as in a subset of neurons and in body wall muscle in later embryos. We are examining regulation of the tbx-2 promoter to understand how pharyngeal muscle is specified in the ABa lineage. Based on results from a feeding RNAi screen of an expanded transcription factor library, I have found that tbx-2 promoter activity is repressed by the NF-Y CCAAT-binding complex and by TBX-2 autoregulatory activity. RNAi knockdown of either NF-Y components or TBX-2 results in strong ectopic expression of tbx-2 promoter::gfp in tissues that do not normally express tbx-2. I plan to pursue these observations by asking if NF-Y and TBX-2 repress endogenous tbx-2 expression, by identifying cis-elements in the tbx-2 promoter targeted by these factors, and by determining if NF-Y and TBX-2 repress tbx-2 expression in the embryo. To identify additional mechanisms regulating tbx-2 expression I am also characterizing a tbx-2 transcriptional enhancer that is necessary and sufficient for expression in the embryonic pharynx. My objective is to identify cis-acting sequences important for enhancer activity, and to identify and functionally characterize candidate regulators of tbx-2 expression that target these sequences. Finally, I will carry out an RNAi-based screen to identify transcription factors regulating tbx-2 as genetic enhancers of a weak tbx-2 mutant. Collectively these aims will elucidate the developmental pathway regulating tbx-2 expression and specifying ABa-derived pharyngeal muscle fate.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
5F31GM090675-03
Application #
8209031
Study Section
Special Emphasis Panel (ZRG1-IMST-E (29))
Program Officer
Hagan, Ann A
Project Start
2010-01-26
Project End
2013-01-25
Budget Start
2012-01-26
Budget End
2013-01-25
Support Year
3
Fiscal Year
2012
Total Cost
$35,774
Indirect Cost
Name
University of Illinois at Chicago
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
098987217
City
Chicago
State
IL
Country
United States
Zip Code
60612
Milton, Angenee C; Packard, Adelaide V; Clary, Lynn et al. (2013) The NF-Y complex negatively regulates Caenorhabditis elegans tbx-2 expression. Dev Biol 382:38-47