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(474) REGULATION OF TEMPORAL GENE EXPRESSION DURING SPERMATOGENESIS. Thomas, Kelwyn1,2, Sung, Dae2, Chen, Jian2, Ogunkoya, Yetunde2, 1 Cooperative Reproductive Science Research Center, Atlanta, GA2 Department of Anatomy and Neurobiology, Atlanta, GA ABSTRACT- The program of spermatogenesis is initiated by a subset of the dividing spermatogonial stem cell population within the seminiferous tubules of the testis. This unique program of cellular differentiation subsequently results in the production of spermatozoa. The molecular mechanisms that initiate and regulate this precise program of germ cell differentiation are currently unknown. To elucidate the molecular mechanisms involved in this process, we have identified a number of stage and cell-type-specific candidate genes that are expressed during spermatogenesis utilizing mRNA differential display and cDNA subtraction strategies. These cDNA clones were initially characterized by DNA sequence analysis and all novel sequences were submitted to GENBANK. A comprehensive search of the National Nucleic Acid Databases using FASTA and BLASTN programs indicated that four known and seven novel transcripts were represented among the fifteen cDNAs that were isolated using these methods. The known transcripts include; E2, the ubiquitin activating enzyme, translin, an RNA binding protein, LYAR, a zinc-finger DNA binding protein and protamine 2. The temporal expression patterns of these cDNAs were analyzed using a Reverse Northern Blot constructed from RNA isolated from purified mouse germ cell populations. The spatial and cell-type-specific expression patterns were verified using in situ hybridization on sections through the mouse seminiferous epithelium. This collection of known and novel candidate germ-cell-specific genes characterized in this study will facilitate a detailed examination of the transcriptional and post-transcriptional mechanisms that regulate their spatial and temporal expression patterns during male germ cell differentiation. KEY WORDS: Spermatogenesis, Gene Expression, mRNA Differential Display, cDNA Subtraction |
