Human Disease




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Spermatogenesis is a complex biological process responsible for the development of sperm from Spermatogonial Stem Cells (SSCs) (Clermont, Oko et al. 1993, Cooke and Saunders 2002, Guan, Nayernia et al. 2006). It is divided into three stages: premeiotic, meiotic and postmeiotic (Holstein, Schulze et al. 2003). In the premeiotic stage, SSCs either self-renew to maintain the number of undifferentiated cells or differentiate into spermatogonia (Brinster and Zimmermann 1994, Fuchs, Tumbar et al. 2004, Oatley and Brinster 2008). Spermatogonia divide several times by mitosis and then differentiate into preleptotene spermatocytes on entry into meiosis. In the meiotic stage the preleptotene spermatocytes subsequently undergo leptotene, zygotene, pachytene and diplotene stages of the first meiotic prophase. During these sub-stages, homologous chromosomes align and pair with synaptonemal complex formation and undergo homologous recombination (De Rooij and Russell 2000, Cooke and Saunders 2002, Page and Hawley 2004). With the completion of the first meiotic division, a primary spermatocyte segregates its chromosomes into two secondary spermatocytes. The secondary spermatocytes rapidly undergo the second meiotic division and generate four round haploid spermatids, followed by a post meiotic global remodeling of the round spermatid nucleus leading ultimately to the unique structure of the sperm (Russell 1990, Ward and Coffey 1991). Somatic cells such as leydig cells and sertoli cells also play a number of crucial roles in spermatogenesis, for instance secreting testosterone and supporting spermatogenesis, respectively (Amlani and Vogl 1988, Ge and Hardy 1998, Liu, Yao et al. 2005).

Spermatogenesis is a well conserved, protracted and complex process. Many genes are involved (Matzuk and Lamb 2008). However, gene interactions involved in SSC self-renewal and differentiation, spermatogenesis initiation, meiotic entry, spermiogenesis, sertoli cell and germ cell interaction, germ cells synchronization during the spermatogenesis, remain largely unknown. We have developed a searchable database, SpermatogenesisOnline 1.0, described here. To our knowledge it is the first bioinformatic resource focusing entirely on spermatogenesis. It contains detailed information for 1,666 genes that have been reported to participate in spermatogenesis by manual curation from 30,233 articles from 37 organisms, and 762 genes that are predicted to participate in the regulation of spermatogenesis using our GAS (Greed AUC Stepwise) model. Users can find the genes of interest by searching our web-server based SpermatogenesisOnline 1.0. It will provide detailed information for the query genes: 1) the basic information; 2) the literature information; and 3) other database information. Furthermore, SpermatogenesisOnline 1.0 provides several additional advanced options for users. SpermatogenesisOnline 1.0 is implemented in PHP + MySQL + JavaScript and can be accessed at without registration.

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