The main research interest of my laboratory is the neuroendocrine regulation of pro-opiomelanocortin (POMC) gene expression in the pituitary. In this proposal we will focus on a single transcriptional activator that we have previously described, designated PO-B, which we have shown by mutational analysis contributes to 70% of POMC basal transcription. The PO-B DNA binding site is critically positioned between the POMC TATA box and CAP site which we believe is necessary for its efficient effects on transcriptional induction. PO-B is found in a number of cell types suggesting that PO-B regulates genes other than POMC. Indeed PO-B is highly inducible by differentiating agents in HL-60 pro-myelocytic cells. We have now purified PO-B to homogeneity. Interestingly dephosphorylation of the purified protein increases PO-B DNA binding affinity less than 30-fold. Our experiments will address the hypothesis that the efficient effects of PO-B on POMC and cellular gene transcription are regulated by its phosphorylation status and critical positioning of the PO-B DNA binding element between the TATA box and CAP site. The specific goals are: 1) To obtain a full length PO-B cDNA clone. 2) To develop antibodies to PO-B. 3) To identify the signal transduction pathways that control PO-B function in the pituitary. 4) To utilize oligonucleotide substitution mutational analysis to determine if the effects of the PO-B element are limited to the context of the POMC promoter.5)To determine if the specific interactions of PO-B with DNA that can be detected in vitro represent the interactions of PO-B with the integrated promoter in vivo. 6) To optimize the conditions of our in vitro transcriptions assays such that the effects of purified PO-B on POMC transcription can be reproducibly and sensitively detected.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Modified Research Career Development Award (K04)
Project #
5K04DK002141-04
Application #
2133895
Study Section
Endocrinology Study Section (END)
Project Start
1992-08-01
Project End
1997-07-31
Budget Start
1995-08-01
Budget End
1996-07-31
Support Year
4
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Georgetown University
Department
Pharmacology
Type
Schools of Dentistry
DUNS #
049515844
City
Washington
State
DC
Country
United States
Zip Code
20057
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