Cloning of cDNA encoding rat spermatidal protein TP2 and expression in Escherichia coli

Abstract

Rat spermatidal protein TP2 is a basic nuclear protein containing two atoms of zinc bound per molecule. We report here cloning of complementary DNA encoding rat TP2 by the RT-PCR method. The nucleotide sequence of cloned TP2 cDNA differs at a few positions from the sequence already reported in the literature. We have cloned rat TP2 cDNA into the expression vector pTrc 99A. Upon induction with 1 mMIPTG, there was a low level of expression of TP2 which could be recovered in the soluble form. Recombinant TP2 was purified from the soluble extract of E. coliusing nickel- agarose and heparin - agarose chromatography and was shown to be identical to native rat TP2 as revealed by immunoblotting with anti-rat TP2 antibodies and radioactive ⁶⁵Zn-blotting.