THE GENE ENCODING THE C-GAMMA CATALYTIC SUBUNIT OF CAMP-DEPENDENT PROTEIN-KINASE IS A TRANSCRIBED RETROPOSON

Three different catalytic isoforms of cAMP-dependent protein kinase ha ve been identified (C alpha, C beta, and C gamma), We report the cloni ng and characterization of the human and rhesus monkey genes encoding the testis-specific C gamma subunit. The human C gamma gene is intronl ess with an open reading frame similar to the previously published cDN A sequence. The 3' and 5' flanking regions share high similarity with the C alpha nontranslated regions (82%) also outside the regions corre sponding to the C gamma cDNA. The human gene is flanked by an Alu-rela ted sequence in the 5'-end and there are insertions of two Alu-related sequences in the 3' nontranslated region, The observation that the C gamma gene is intronless and colinear with C alpha mRNA, together with the presence of remnants of a poly(A) tail and flanking direct repeat s, indicates that the C gamma gene is a C alpha-derived retroposon, Th e 5' flanking region of this gene has a high G/C content and a putativ e TATA box situated at -138 compared to the translation initiation cod on. Cloning and sequencing of a partial C gamma rhesus monkey gene dem onstrate conservation of the sequence in primates. Northern analysis o n isolated and fractionated human germ cells of testes from normal and estrogen-treated individuals demonstrates that the C gamma gene is ex pressed only in germ cells in the human testis, Our results indicate t hat the C gamma gene is a retroposon specifically transcribed in prima te testicular germ cells. (C) 1998 Academic Press.