3640 unique est clusters from the medaka testis and their potential use for identifying conserved testicular gene expression in fish and mammals3640独特的est集群青鳉睾丸及其潜在的用于识别守恒的睾丸在鱼类和哺乳动物基因表达.pdf

3640 Unique EST Clusters from the Medaka Testis and Their Potential Use for Identifying Conserved Testicular Gene Expression in Fish and Mammals 1. 2.¤ 1 1,2 1 Lijan Lo , Zhenhai Zhang , Ni Hong , Jinrong Peng *, Yunhan Hong * 1 Department of Biology Sciences, National University of Singapore, National University of Singapore, Singapore, Singapore, 2 Institute of Molecular and Cell Biology, Proteos, Singapore Abstract Background: The fish medaka is the first vertebrate capable of full spermatogenesis in vitro from self-renewing spermatogonial stem cells to motile test-tube sperm. Precise staging and molecular dissection of this process has been hampered by the lack of suitable molecular markers. Methodology and Principal Findings: We have generated a normalized medaka testis cDNA library and obtained 7040 high quality sequences representing 3641 unique gene clusters. Among these, 1197 unique clusters are homologous to known genes, and 2444 appear to be novel genes. Ontology analysis shows that the 1197 gene products are implicated in diverse molecular and cellular processes. These genes include markers for all major types of testicular somatic and germ cells. Furthermore, markers were identified for major spermatogenic stages ranging from spermatogonial stem cell self-renewal to meiosis entry, progression and completion. Intriguingly, the medaka testis expresses at least 13 homologs of the 33 mouse X-chromosomal genes that are enriched in the testis. More importantly, we show that key components of several signaling pathways known to be important for testicular function in mammals are well represented in the medaka testicular EST collection. Conclu