Abstract

Insulin-like growth factor binding protein-5 (IGFBP-5) is produced by osteoblasts and potentiates IGF mitogenic actions in osteoblast cultures. Progesterone (PG) increases osteoblast proliferation and increases osteoblast IGFBP-5 expression. Mechanisms underlying PG induction of IGFI3P-5 expression were investigated in U2 human osteosarcoma cells. In nuclear run-on analyses, PG increased IGF)3P-5 gene transcription to 400% of control. To define the underlying mechanisms, the human IGF13P-5 gene proximal promoter was cloned and sequenced. The proximal 500 bp of this region contains TATA and CAAT boxes, five putative PG response element (PRE) half-sites and two tandem CACCC boxes. Chloramphenicol acetyltransferase (CAT) reporter constructs containing up to 753 bp of the human IGFBP-5 gene 5'-flanking sequence were made. In U2 cells transfected with reporter construct pCAT753 containing positions -753 to t23, PG increased CAT activity to 134% of untreated control activity (P

LLU Discipline

Biochemistry

Department

Biochemistry

School

Graduate School

First Advisor

Thomas A. Linkhart

Second Advisor

Donna D. Strong

Third Advisor

Subburaman Mohan

Fourth Advisor

R. Bruce Wilcox

Fifth Advisor

Aladar A. Szalay

Sixth Advisor

John F. Sands

Degree Name

Doctor of Philosophy (PhD)

Degree Level

Ph.D.

Year Degree Awarded

1996

Date (Title Page)

6-1996

Language

English

Library of Congress/MESH Subject Headings

Progesterone; Insulin-Like Growth-Factor-Binding-Protein 5; Reverse Transcriptions; Osteoblasts

Type

Dissertation

Page Count

xii; 175

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

Included in

Biochemistry Commons

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