Progesterone Regulation of Insulin like-Growth Factor : Binding Protein-5 Gene Transcription in Human Osteoblasts

<p>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</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biochemistry

Year

1996

Author dc:creator

• Boonyaratanakornicit, Viroj

Contributors dc:contributor

• Thomas A. Linkhart
• Donna D. Strong
• Subburaman Mohan
• R. Bruce Wilcox
• Aladar A. Szalay
• John F. Sands

• Biochemistry
• Biochemistry, Biophysics, and Structural Biology
• Progesterone; Insulin-Like Growth-Factor-Binding-Protein 5; Reverse Transcriptions; Osteoblasts

Statement dc: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.

Language dc:language

English

Repository record dc:identifier

https://scholarsrepository.llu.edu/etd/658

OAI identifier oai:identifier

oai:scholarsrepository.llu.edu:etd-1680