Identification of a testis-specific gene from the mouse t-complex next to a CpG-rich island

We have used an approach based on the observation of CpG-rich regions near the 5' end of many genes to screen a panel of cosmids derived from the t-complex and tested candidate sequences for evidence of transcription in a number of different mouse tissues. One gene so identified is expressed specifically in testicular germ cells and maps to a subregion of the t-complex also containing loci involved in transmission ratio distortion and male sterility. The transcript is first detected during the pachytene stage of the first meiotic division, but is expressed in highest levels in the later haploid spermatogenic stages. Sequence analysis verified the existence of a CpG-rich element on the 5' end of the gene and predicts a unique protein species with no significant homologies to those previously determined.