HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 71/2/375    most recent biolreprod.104.028225v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Siu, M. K.Y. Articles by Cheng, C. Y. Search for Related Content PubMed PubMed Citation Articles by Siu, M. K.Y. Articles by Cheng, C. Y. Agricola Articles by Siu, M. K.Y. Articles by Cheng, C. Y.

Extracellular Matrix: Recent Advances on Its Role in Junction Dynamics in the Seminiferous Epithelium During Spermatogenesis¹

Population Council, Center for Biomedical Research, New York, New York 10021

Spermatogenesis takes place in the seminiferous epithelium of the mammalian testis in which one type A1 spermatogonium (diploid, 2n) gives rise to 256 spermatids (haploid, 1n). To accomplish this, developing germ cells, such as preleptotene and leptotene spermatocytes, residing in the basal compartment of the seminiferous epithelium must traverse the blood-testis barrier (BTB) entering into the adluminal compartment for further development into round, elongating, and elongate spermatids. Recent studies have shown that the basement membrane in the testis (a modified form of extracellular matrix, ECM) is important to the event of germ cell movement across the BTB because proteins in the ECM were shown to regulate BTB dynamics via the interactions between collagens, proteases, and protease inhibitors, possibly under the regulation of cytokines. While these findings are intriguing, they are not entirely unexpected. For one, the basement membrane in the testis is intimately associated with the BTB, which represents the basolateral region of Sertoli cells. Also, Sertoli cell tight junctions (TJs) that constitute the BTB are present side-by-side with cell-cell actin-based adherens junctions (AJ, such as basal ectoplasmic specialization [ES]) and intermediate filament-based desmosome-like junctions. As such, the relative morphological layout between TJs, AJs, and desmosome-like junctions in the seminiferous epithelium is in sharp contrast to other epithelia where TJs are located at the apical portion of an epithelium or endothelium, furthest away from ECM, to be followed by AJs and desmosomes, which in turn constitute the junctional complex. For another, anchoring junctions between a cell epithelium and ECM found in multiple tissues, also known as focal contacts (or focal adhesion complex, FAC, an actin-based cell-matrix anchoring junction type), are the most efficient junction type that permits rapid junction restructuring to accommodate cell movement. It is therefore physiologically plausible, and perhaps essential, that the testis is using some components of the focal contacts to regulate rapid restructuring of AJs between Sertoli and germ cells when germ cells traverse the seminiferous epithelium. Indeed, recent findings have shown that the apical ES, a testis-specific AJ type in the seminiferous epithelium, is equipped with proteins of FAC to regulate its restructuring. In this review, we provide a timely update on this exciting yet rapidly developing field regarding how the homeostasis of basement membrane in the tunica propria regulates BTB dynamics and spermatogenesis in the testis, as well as a critical review on the molecular architecture and the regulation of ES in the seminiferous epithelium.

¹ Supported in part by grants from the National Institutes of Health (NICHD, U01 HD45908 to C.Y.C.; U54 HD29990, Project 3 to C.Y.C.), the CONRAD Program (CICCR, CIG 96-05-B and CIG 01-72), and the Noopolis Foundation.

² Correspondence: C. Yan Cheng, Population Council, 1230 York Avenue, New York, NY 10021. FAX: 212 327 8733;y-Cheng{at}popcbr.rockefeller.edu

This article has been cited by other articles:

				M. K. Y. Siu, C.-h. Wong, W. M. Lee, and C. Y. Cheng Sertoli-Germ Cell Anchoring Junction Dynamics in the Testis Are Regulated by an Interplay of Lipid and Protein Kinases J. Biol. Chem., July 1, 2005; 280(26): 25029 - 25047. [Abstract] [Full Text] [PDF]

				C.-h. Wong, D. D. Mruk, M. K. Y. Siu, and C. Y. Cheng Blood-Testis Barrier Dynamics Are Regulated by {alpha}2-Macroglobulin via the c-Jun N-Terminal Protein Kinase Pathway Endocrinology, April 1, 2005; 146(4): 1893 - 1908. [Abstract] [Full Text] [PDF]

				C.-H. Wong, W. Xia, N. P. Y. Lee, D. D. Mruk, W. M. Lee, and C. Y. Cheng Regulation of Ectoplasmic Specialization Dynamics in the Seminiferous Epithelium by Focal Adhesion-Associated Proteins in Testosterone-Suppressed Rat Testes Endocrinology, March 1, 2005; 146(3): 1192 - 1204. [Abstract] [Full Text] [PDF]