Germ cell-less like-2 protein is a new component of outer dense fibers in rat sperm flagella

Abstract

We have analyzed the expression profiles of ten genes in terms of testis development and organ specificity in rat, which were selected from 215 round spermatid-specific transcripts listed in a database. Out of the ten genes, we directed our attention to one gene, a germ cell-less like-2 gene (gcl-2), a homolog of Drosophila gcl gene (gcl), which is a component of the germ plasma and required for primordial germ cell formation. Rat genome contains duplicate rat gcl-2 (rgcl-2) genes, rgcl-2A and rgcl-2B, both of which are located at Xq13. RT-PCR analysis showed that the expression of the two genes was up-regulated during testis development and that they were predominantly expressed in the testis. Both rgcl-2A and rgcl-2B encode a protein of 498 amino acid residues, showing 90.56% identity at the amino acid level. Confocal laser scanning microscopy revealed that rgcl-2 protein was synthesized in the cytoplasm of elongating spermatids and at least a part of it was integrated into the middle piece of spermatozoa during spermiogenesis. Immunogold electron microscopy uncovered that rgcl-2 was localized at the abaxial (convex) surface of outer dense fibers (ODF) of rat sperm flagella. Therefore, we concluded that rgcl-2 is a new component of ODF in sperm flagella. Reproduction (2007) 134 749-756

The Spermatozoon

“…316 It is localized at the abaxial (convex) surface of outer dense fibers. 316 It is localized at the abaxial (convex) surface of outer dense fibers.…”

Sperm flagella: comparative and phylogenetic perspectives of protein components

“…Although they vary among species, mammalian ODFs consist of at least 14 polypeptides with apparent molecular masses of 11-87 kDa (Oko, 1988;Vera et al, 1984), including three major proteins: leucine zipper protein ODF1 (Morales et al, 1994), ODF-interacting leucine zipper protein ODF2 (Shao et al, 1997) and 32-kDa coiled-coil protein ODF3 (previously named SHIPPO 1; Egydio de Carvalho et al, 2002). Other ODF proteins and their associated proteins have also been characterized, such as a polyamine-modulated factor 1 binding protein (Petersen et al, 2002; called ODF3 in the original paper), the product of a germ cell-less like-2 gene (gcl-2) (Murayama et al, 2007), kinesin LC3 as a binding partner of ODF1 (Bhullar et al, 2003), voltage-dependent anion selective channels (VDAC; Hinsch et al, 2004), SPAG4 (Shao et al, 1999), SPAG5 (Shao et al, 2001), CDK5 (Rosales et al, 2004), tektin 2 (Shimasaki et al, 2010), tektin 4 (Iida et al 2006;Roy et al, 2007) and Spetex-1 (Kaneko et al, 2010). Tektins are believed to be structural flagellar proteins that confer stability to doublet microtubules (Nojima et al, 1995).…”

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 3: Developmental changes in spermatid flagellum and cytoplasmic droplet and interaction of sperm with the zona pellucida and egg plasma membrane

“…Interestingly, Tekt4-null mice in a mixed genetic background appear to have almost normal fertility, while those in a 129-inbred background are subfertile (Roy et al, 2007 Nayernia et al, 2002;Pearse et al, 1997;Yu et al, 2000). Tektin 5 [ID: T3-414] is found in the midpiece of the flagellum on the inner side of the mitochondrial sheath; it may serve for flagellar stability and sperm motility (Murayama et al, 2007(Murayama et al, , 2008.…”