Differential expression of two testis-specific transcripts of the mouse Pdha-2 gene during spermatogenesis.

Analysis of the expression of the testis-specific isoform of the mouse pyruvate dehydrogenase E1 alpha subunit gene (Pdha-2) during various stages of spermatogenesis has shown that a 2.0-kb Pdha-2 mRNA is initially transcribed in meiotic prophase. The initial appearance of Pdha-2 mRNA precedes that of Pgk-2 and corresponds to the appearance of Ldh-3 mRNA. A second Pdha-2 1.7-kb transcript is present in post-meiotic round spermatids. Polysomal analysis of purified spermatogenic cell populations demonstrates that the 2.0-kb mRNA species is translated in diploid, pachytene spermatocytes and the 1.7-kb mRNA species is translated in round spermatids, although a large proportion is present on the nonpolysomal fraction and may be stored for use in later stages of spermiogenesis.