Description
We report a comprehensive large-scale expression profiling analysis of mammalian male germ cells undergoing mitotic growth, meiosis and gametogenesis using High Density Oligonucleotide Microarrays and highly enriched cell populations. Among 11955 rat loci investigated, 1268 were identified as differentially transcribed in germ cells at subsequent developmental stages as compared to total testis, somatic Sertoli cells as well as brain and skeletal muscle controls. The loci were organized into four expression clusters that correspond to somatic, mitotic, meiotic and post-meiotic cell types. This work provides information about expression patterns of approximately 200 genes known to be important during male germ cell development. Approximately 40 of those are included in a group of 121 transcripts for which we report germ cell expression and lack of transcription in three somatic control cell types. Moreover, we demonstrate the testicular expression and transcriptional induction in mitotic, meiotic and/or post-meiotic germ cells of 293 as yet uncharacterized transcripts some of which are likely to encode factors involved in spermatogenesis and fertility. This group also contains numerous potential germ cell specific targets for innovative contraceptives. A graphical display of the data is conveniently accessible through the GermOnline database at <a href="http://www.germonline.org" target="_blank">http://www.germonline.org</a>.