This revised application describes studies to elucidate the functional role and molecular mechanism of action of tif, a new member of the axl family of receptors. Tif, which was cloned by RTPCR from a K562 library, is an extremely interesting receptor in that it bears extracellular fibronectin domains as well as Ig domains, suggesting a role in cell-matrix attachment and signalling. In addition, its pattern of RNA expression, gonad>brain>other tissues, suggests a potential role in primitive cell maintenance and self-renewal. In this application, the Applicant proposes to: 1) Study the transforming potential of tif by enforced over- expression; 2) Investigate the role of tif in hematopoietic determination and differentiation by analyzing the phenotype of both K562 and Ba/F3 cells constitutively expressing activated tif, and by differentiating ES cells with a targeted gene disruption of the tif locus; 3)Identify the immediate downstream components of the tif signaling pathway via immonocoprecipitation and via the yeast two-hybrid system; 4)Search for a functional interaction between tif and the Epo receptor by enforced expression of an EpoR/tif chimera, analyzing signal transduction and cellular phenotype in transfected Ba/F3 and K562 cells; and 5)Identify and clone the tif ligand via expression or affinity column chromatography. These studies are designed to provide the first important steps towards understanding the role of Tif in hematopoietic differentiation.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
1R01CA059985-01A2
Application #
2100592
Study Section
Hematology Subcommittee 2 (HEM)
Project Start
1995-07-01
Project End
2000-04-30
Budget Start
1995-07-01
Budget End
1996-04-30
Support Year
1
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of Cincinnati
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
City
Cincinnati
State
OH
Country
United States
Zip Code
45221