Dr. Gelehrter's laboratory has previously demonstrated that incubation of rat hepatoma cells with cyclic nucleotides results in decreased transcription from the type 1 plasminogen activator inhibitor (PAI-1) gene as well as a 3-fold increase in the rate of PAI-1 mRNA decay. The half- life of PAI-1 mRNA in HTC cells is 4.5 hours; after incubation with cyclic nucleotides, PAI-1 mRNA decays with a half-life of 1.5 hours after a 2 hour lag period. The objective of this proposal is to establish a cell- free, in vitro mRNA degradation assay system for PAI-1 mRNA and to use this system to determine the cis-acting sequences in PAI-1 mRNA and identify the trans-acting HTC cell factors that are responsible for the cyclic nucleotide-mediated destabilization of PAI-1 mRNA in HTC cells. The in vitro system is advantageous because: (i) it allows analysis of mRNA degradation without the use of transcriptional inhibitors, (ii) it allows analysis of cytoplasmic events independently of nuclear events, (iii) it may allow for the detection of mRNA decay intermediates, (iv) it may be possible to use synthetic mutant PAI-1 mRNAs to identify nucleic acid sequences involved in both basal and cyclic nucleotidc-regulated PAI- 1 mRNA decay, and (v) it provides a facile system for identifying and characterizing the trans-acting factors regulating PAI-1 mRNA degradation. Regulation of mRNA stability is, as yet, poorly understood. To date, the best studied systems are ones in which mRNAs are stabilized in the presence of hormones. The regulation of PAI-1 mRNA by cyclic nucleotides provides a favorable experimental system in which to examine hormonally- induced mRNA destabilization. Through the proposed studies, we will be able to explore the molecular mechanisms by which cyclic nucleotides regulate PAI-1 mRNA stability. Furthermore, results from these studies will provide important information about both constitutive and hormonally regulated pathways of mRNA degradation.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32DK009437-02
Application #
2391286
Study Section
Special Emphasis Panel (ZRG2-END (01))
Program Officer
Hyde, James F
Project Start
1997-04-01
Project End
Budget Start
1997-04-01
Budget End
1998-03-31
Support Year
2
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Genetics
Type
Schools of Medicine
DUNS #
791277940
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109