doi:10.1369/jhc.5A6688.2005
Volume 53 (10): 1235-1243, 2005 Copyright ©The Histochemical Society, Inc. Stage-specific Expression of Dynein Light Chain-1 and Its Interacting Kinase, p21-activated Kinase-1, in Rodent Testes : Implications in Spermiogenesis
Department of Molecular and Cellular Oncology (R-AW,RK) and Department of Experimental Radiation Oncology (MZ,MLM), UT-M.D. Anderson Cancer Center, Houston, Texas Correspondence to: Rakesh Kumar, PhD, Department of Molecular and Cellular Oncology, Box 108, UT-M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030. E-mail: rkumar{at}mdanderson.org Mammalian spermatogenesis is a complex process involving regulatory interactions of many gene products. In this study, we found that dynein light chain-1 (DLC1), a component of the dynein motor complex, is highly expressed in mouse and rat testes. Immunohistochemically detectable levels of DLC1 are observed specifically in spermatids in steps 916 in distinct subcellular compartments: in steps 911, DLC1 is predominantly localized in the nucleus; in steps 12 and 13, it is found in both nucleus and cytoplasm; and in step 1416, it is present exclusively in the cytoplasm. In addition, we found p21-activated kinase 1 (Pak1), a protein kinase that activates DLC1 by phosphorylating DLC1 at Serine 88, was also expressed during these stages of spermatogenesis. Pak1 was also expressed in Leydig cells, in preleptotene primary spermatocytes, and in round spermatids. The spermiogenic stagespecific expression of DLC1 suggests a role for DLC1 in chromatin condensation, spermatid shaping, and the final release of sperm from the spermatogenic epithelium. Further, Pak1 may also play a role in spermiogenesis by regulating DLC1 phosphorylation and, consequently, its function. (J Histochem Cytochem 53:12351243, 2005)
Key Words: DLC1 Pak1 testis spermatogenesis
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