Cloning of cDNA for rat pro alpha 1(V) collagen mRNA. Expression patterns of type I, type III and type V collagen genes in experimental granulation tissue

A cDNA clone for rat pro alpha 1(V) collagen mRNA was constructed using PCR amplification, with primers based on human and hamster COL5A1 gene sequenc es. The clone pRCVA1 is 560 nucleotides long and it encodes for the carboxy propeptide of type V procollagen. Homology shared with type I collagen seq uence was 64%, with type IT collagen 65% and with type In collagen 61%. To evaluate the spatial and temporal expression of type V collagen mRNA in wou nd healing model, subcutaneously implanted viscose cellulose sponges in rat s were used to induce granulation tissue formation, Analyses on granulation tissue were carried out on days 5, 8, 14, 21, 30, 59 and 84, Specific cDNA probes to pro alpha 1(I), pro alpha 1(III) and pro alpha 1(V) collagen mRN A were used in slot blot, Northern and in situ hybridization, Type I collag en gene expression was upregulated at the initial stage of wound healing, t ype III collagen gene expression was constant and from the day 14 onwards t ype I and III collagen gene expressions were at the same level. Type V coll agen gene expression was seen at every time point studied but at a consider ably lower level than type I and III collagens. In situ hybridization showe d that type V collagen was expressed in two different cell types. In conclu sion, type V collagen was expressed in the wound healing model from at leas t day 5 onwards and it was synthesized by fibroblast-like and rounded cells .