Volume 4 • Issue 1 • 1000139 J Cell Sci Ther ISSN: 2157-7013 JCEST, an open access journal Open Access Research Article Alhad Ashok Ketkar and KVR Reddy, J Cell Sci Ther 2013, 4:1 DOI: 10.4172/2157-7013.1000139 Keywords: Spermatogenesis; Spermatogonial stem cells (SSCs); Microarray; days post partum (dpp) Introduction Spermatogenesis is a complex and well-orchestrated process, in which Spermatogonial Stem Cells (SSCs) divide and diferentiate to produce unlimited numbers of mature spermatozoa. Tis process is continuous throughout the adult life in most mammals. Te seminiferous epithelium consists of only one somatic cell type, sertoli cell [1] and many diferent germ cell types [2]. Sertoli cells play a nurturing role in coordinating and supporting important events of spermatogenesis which occurs in mitotic, meiotic and post meiotic phases. Spermatogenesis is initiated by the division of stem cells (primitive type A spermatogonia) to form type B spermatogonia. Tese diferentiated spermatogonial cells enter a meiotic prophase as pre- leptotene spermatocytes. Te spermatocytes continue to mature as they go through the leptotene, zygotene and pachytene phases of meiosis. At the end of meiotic prophase, they undergo the fnal meiotic division to form haploid spermatids. Tese spermatids undergo spermiogenesis to form mature spermatozoa [3]. Tis complex process is orchestrated through expression of thousands of genes encoding proteins which are developmentally regulated during spermatogenesis and play essential roles during specifc phases of germ cell development. Both transcriptional and translational control mechanisms are responsible for temporal and stage-specifc expression pattern of genes [4,5]. Each cell contains the same genome, but not all the genes are used in each cell. Some genes are expressed when needed and many genes are used to specify features unique to each type of cells. In order to understand how genes are controlled and expressed at specific time and which genes function uniquely in special cells, an important step is defining gene expression profiles i.e. comparing patterns of gene expression in different tissues and at different developmental stages, in normal versus treated or diseased states. This can be accomplished by RT-PCR, RNase protection assays or Northern blot analysis, but these methods focus on only a few genes at a time. A more promising approach for analyzing multiple genes simultaneously is the hybridization of entire cDNA populations to nucleic acid arrays such as microarray, a method adopted for high- throughput analysis of gene expression [6-9]. In a similar vein, microarray technology can be applied to gain a comprehensive view of expression pattern of genes involved in early stages of spermatogenesis with the purpose of studying the mechanisms and regulation of spermatogenesis at the genetic level. In rodents, frst wave of spermatogenesis sets the basis for spermatogenesis process in adult animals. In mouse, at 0 days post partum (dpp), gonocytes are in the quiescent stage, around 3 dpp gonocytes are converted into SSCs which then migrate to the basement membrane of seminiferous tubules, at 5 dpp proliferation of SSCs starts, at 10 and 20 dpp spermatocytes and spermatids appear, and at 35 dpp frst appearance of spermatozoa thereby marking the end of the frst wave of spermatogenesis [10,11]. In our earlier studies, we deduced the expression patterns of Oct-4 as well as Plzf and functional signifcance of Oct-4 during the early stages of spermatogenesis in mice [12,13]. Both Oct-4 and Plzf are known to be expressed in undiferentiated SSCs and considered to be important for SSC self-renewal. Te results of study showed Oct-4 and Plzf expression to be highest in the testes of 10 dpp mice both at the mRNA and protein level [12]. Apart from Oct-4 and Plzf, the SSC self-renewal and proliferation process involves many other genes which are crucial to maintain SSCs in the undiferentiated state. Terefore, the main aim of the present study is to elucidate the expression pattern of all those *Corresponding authors: KVR Reddy, Division of Molecular Immunology and Microbiology (MIM), National Institute for Research in Reproductive Health (NIRRH), JM Street, Parel, Mumbai-400012, India, Tel: +91-22-24192016; Fax: +91-22-24139412; E-Mail: reddyk@nirrh.res.in Received December 19, 2012; Accepted March 19, 2013; Published March 21, 2013 Citation: Alhad Ashok Ketkar, KVR Reddy (2013) Differential Expression of Genes Involved in Early Events of Spermatogenesis in Mice. J Cell Sci Ther 4: 139. doi:10.4172/2157-7013.1000139 Copyright: © 2013 Ketkar AA, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Spermatogenesis is a highly complex process involved in the transmission of genetic information from one generation to next generation. The process takes place in the seminiferous tubules of the testis and is regulated by genes that control cell division, cell-cell interaction and morphogenetic changes in both the somatic and germ cell lineages in a highly orchestrated pattern. The frst wave of spermatogenesis in mouse is typically characterized by the differential expression of genes involved in spermatogenesis. The purpose of this study was to analyze the differential expression of genes involved in Spermatogonial Stem Cells (SSCs) self-renewal, proliferation and differentiation using microarray approach in the testes of 35 vs. 5 Days Post Partum (dpp) mice. Our results demonstrate that genes involved in SSC self-renewal and proliferation were signifcantly down-regulated while genes involved in SSC differentiation were signifcantly up-regulated in the testes of 35 vs. 5 dpp mice. There was up-regulation in the expression of genes involved in cell cycle regulation. Pro-apoptotic genes were found to be up- regulated on the contrary anti-apoptotic genes were down-regulated in the testes of 35 vs. 5 dpp mice. Thus, our study helps in understanding the differential expression profle of genes involved in early stages of spermatogenesis in mice. Differential Expression of Genes Involved in Early Events of Spermatogenesis in Mice Alhad Ashok Ketkar and KVR Reddy* Division of Molecular Immunology and Microbiology (MIM), National Institute for Research in Reproductive Health (NIRRH), JM Street, Parel, Mumbai-400012, India J o u r n a l o f C e l l S c i e n c e & T h e r a p y ISSN: 2157-7013 J o u r n a l o f C e l l S c i e n c e & T h e r a p y ISSN: 2157-7013 Journal of Cell Science & Therapy Journal of Cell Science & Therapy