Cloning and expression of activator of CREM in testis in human testicular tissue

Activator of cAMP-responsive element modulator (CREM) in testis (ACT) has r ecently been found in the mouse testis where it activates CREM, a transcrip tion factor essential for the differentiation of spermatids into mature spe rmatozoa. The importance of CREM in human spermatogenesis prompted us to ex amine whether ACT was also present in the human testis, Western blot analys is, performed with an anti-mouse ACT serum, showed the presence of a single immunoreactive band of a size similar to murine ACT, A library screening r esulted in the isolation and characterization of the complete cDNA which sh owed 88% homology with the mouse counterpart, The human ACT gene is compose d of five coding exons, being the first untranslated, and the mRNA spans 83 5 nucleotides coding for a 284 amino acid protein, Expression studies by RT -PCR confirmed that ACT is present in normal human testis. The human ACT ge ne is localized on the chromosome 6. (C) 2001 Academic Press.