Basic Fibroblast Growth Factor-Like Substance Associates with DNA in Germ Cell Nuclei

Our previous work has demonstrated that immunoreactive basic fibroblast growth factor (bFGF)-like substance presents in germ cell nuclei of adult rat testis. In the present study, interactions of bFGF-like substance with a sub-nuclear material were investigated. When nuclear extract from adult rat germ cell was analysed by heparin-Sepharose affinity chromatography and Western blot, germ cell nuclei contained 2 forms of bFGF-like substances with molecular weights of 16.5 and 24.5 kDa. The immunoreactivity for bFGF-like substance of germ cell nuclei decreased after treatment with either micrococcal nuclease or DNase I. Furthermore, South-Western blots analysis revealed these 2 forms of bFGF-like substance bind with high affinity to the exogenous salmon testis DNA. Thus, these results suggest that the bFGF-like substances are associated with DNA in the germ cel.