The rat endozepine-like peptide gene is highly expressed in late haploid stages of male germ cell development

The structure of the endozepine-like peptide (ELP) gene is closely related to the intracellular acyl-CoA binding protein (ACBP), but unlike the genera lized distribution of the latter, it is restricted to the male germ cells o f the testis. In the present study a combination of nonradioactive in situ mRNA hybridization and immunohistochemistry was used to precisely determine the cellular expression patterns of ELP mRNA and protein in control and me thoxyacetic acid (MAA)-treated rat testes. ELP transcripts are first detect able in late stages (step 6) of round spermatids, with transcription increa sing through late-elongating steps. Translation of the ELP mRNA is delayed, with first immunohistochemical staining occurring in elongated spermatids at step 16, and protein accumulating through step 19. ELP immunoreactivity proves to be an excellent marker for late spermatid stages and highlights t he presumably clonal recovery of spermatids following MAA treatment.