RT Journal Article SR Electronic T1 Functional transformation of the chromatoid body in mouse spermatids requires testis-specific serine/threonine kinases JF Journal of Cell Science JO J. Cell Sci. FD The Company of Biologists Ltd SP 331 OP 339 DO 10.1242/jcs.059949 VO 123 IS 3 A1 Shang, Peng A1 Baarends, Willy M. A1 Hoogerbrugge, Jos A1 Ooms, Marja P. A1 van Cappellen, Wiggert A. A1 de Jong, Antonius A. W. A1 Dohle, Gert R. A1 van Eenennaam, Hans A1 Gossen, Jan A. A1 Grootegoed, J. Anton YR 2010 UL http://jcs.biologists.org/content/123/3/331.abstract AB The cytoplasmic chromatoid body (CB) organizes mRNA metabolism and small regulatory RNA pathways, in relation to haploid gene expression, in mammalian round spermatids. However, little is known about functions and fate of the CB at later steps of spermatogenesis, when elongating spermatids undergo chromatin compaction and transcriptional silencing. In mouse elongating spermatids, we detected accumulation of the testis-specific serine/threonine kinases TSSK1 and TSSK2, and the substrate TSKS, in a ring-shaped structure around the base of the flagellum and in a cytoplasmic satellite, both corresponding to structures described to originate from the CB. At later steps of spermatid differentiation, the ring is found at the caudal end of the newly formed mitochondrial sheath. Targeted deletion of the tandemly arranged genes Tssk1 and Tssk2 in mouse resulted in male infertility, with loss of the CB-derived ring structure, and with elongating spermatids possessing a collapsed mitochondrial sheath. These results reveal TSSK1- and TSSK2-dependent functions of a transformed CB in post-meiotic cytodifferentiation of spermatids.