Cutaneous rat wounds express C49a, a novel gene with homology to the humanmelanoma differentiation associated gene, Mda-7

We have used DD-PCR (differential display-polymerase chain reaction) to ide ntify new genes that are over- or underexpressed during wound repair. DD-PC R performed on excisional wounds identified the expression of rat c49a. Clo ning and sequence analysis of the rat c49a gene revealed high homology to a novel human melanoma differentiation associated gene, mda-7. The human mda -7 gene isolated from melanoma cell lines, has been linked with human melan oma differentiation, and growth suppression. Moreover, transfection of huma n mda-7 constructs into human tumor cells suppresses the growth and colony formation of tumor cells from diverse origins. To confirm and relatively qu antitate expression of rat c49a gene during repair, specific primer, reduce d cycle RT-PCR (reverse transcription-PCR) was performed. RT-PCR showed an similar to 9 to 12-fold elevation of rat c49a mRNA at 12 h to 5 days above nonwounded controls that gradually decreased to similar to 1.5 to 3-fold by day 14. Cloning and sequence analysis of the entire 1200 base pair c49a ge ne product showed 78% nucleotide homology to human mda-7. Immunohistochemis try studies localized rat C49A expression primarily to fibroblast-like cell s at the wound edge and base. The marked up-regulation of rat c49a transcri pts during the inflammatory and early granulation tissue phases of wound re pair where cellular processes such as re-epithelialization, angiogenesis, a nd fibroplasia predominate-suggest that c49a is associated with proliferati on of fibroblasts in wound healing. I. Cell. Biochem. 74:1-10, 1999. (C) 19 99 Wiley-Liss, Inc.