Transcriptional regulation of an axonemal central apparatus gene, sperm-associated antigen 6, by a SRY-related high mobility group transcription factor, S-SOX5.

SOX5 is a transcription factor with homology to the high mobility group box region of the testis-determining factor, SRY. Both the mouse and human SOX5 genes encode a 48-kDa SOX5 protein (S-SOX5) that is only present in tissues containing cells with motile cilia/flagella. The mammalian sperm-associated antigen 6 gene (SPAG6) encodes an axoneme central apparatus protein.

MEIG1 is essential for spermiogenesis in mice.

Spermatogenesis can be divided into three stages: spermatogonial mitosis, meiosis of spermatocytes, and spermiogenesis. During spermiogenesis, spermatids undergo dramatic morphological changes including formation of a flagellum and chromosomal packaging and condensation of the nucleus into the sperm head. The genes regulating the latter processes are largely unknown.

Apoptosis induces expression of sphingosine kinase 1 to release sphingosine-1-phosphate as a "come-and-get-me" signal.

Sphingosine-1-phosphate (S1P) is a bioactive lipid that regulates myriad important cellular processes, including growth, survival, cytoskeleton rearrangements, motility, and immunity. Here we report that treatment of Jurkat and U937 leukemia cells with the pan-sphingosine kinase (SphK) inhibitor N,N-dimethylsphingosine to block S1P formation surprisingly caused a large increase in expression of SphK1 concomitant with induction of apoptosis. Another SphK inhibitor, D,L-threo-dihydrosphingosine, also induced apoptosis and produced dramatic increases in SphK1 expression.