Molecular probes for general testicular and specific spermatogenic function

Northern analysis of human testis poly(A+) RNA with a mixture of oligonucleotide primer extended cDNA probes revealed several similar RNAs. These RNAs were subsequently cloned into a VPCS (vector-primer-cloner-sequencer) plasmid. One of these clones, NDHu1, was represented within the library a number of times and hybridized strongly to a poly(A+) RNA of congruent to 1.2 kb. Sequence analysis identified this clone as the URF 1 subunit of the mitochondrial NADH dehydrogenase (NDHu1). Comparison of the relative levels of the NDHu1 and human protamine 1 (HP1) transcripts revealed that HP1 was less abundant than NDHu1. This was unexpected, since it is known that within differentiating mammalian spermatid cells, protamine (HP1) is an abundant transcript. This suggested that the ratio of the relative levels of these two very different mRNAs was indicative of the relationship between specific spermatogenic function (germ cell transcription, determined by the level of the HP1 transcript) and general testicular cell function (determined by the level of the mitochondrial mRNAs, i.e. NDHu1). This correlation was maintained when several individuals expressing various degrees of testicular dysfunction were examined. This study suggests that these probes may be useful markers for general testicular and specific spermatogenic function.