Gene expression in mouse testis during development
Many genes and cellular pathways have been implicated in the initiation and regulation of testicular differentiation, development and function. The genes generally have a temporal expression profile. This study aimed to characterise several of the key genes involved in the androgen synthetic pathway, in both normal mice and also mutant strains. LH receptor and 5 a reductase were the two major genes of interest. Using molecular biology techniques it was established that the LH receptor exists in several forms throughout development, with smaller, alternate-spliced forms being the predominant transcripts expressed in testis during fetal life. It is inconclusive from this study whether these spliced forms encode functional proteins, but the consistency of their expression patterns suggests that they do. Expression levels of the two isoforms of 5 a reductase were found to be very low in mouse testis throughout development, and in addition androgen may be involved in regulation of expression of the type 1 isoform, as levels were significantly reduced in the AR-null mouse testis both at puberty and adulthood. Previously unpublished sequence from both type 1 and type 2 5 a reductase transcripts was obtained using PCR primers designed from rat sequence and mouse EST sequence. The results from this study highlight the importance specific genes play in regulation and expression of others and the down stream signalling pathways which may be involved in development and regulation of a functional testis.