SRY-related genes in the genome of the rice field eel (Monopterus albus)

Abstract

-The mammalian sex determining gene, SRY, is the founding member of the new growing family of Sox (SRY-like HMG-box gene) genes. Sox genes encode transcription factors with diverse roles in development, and a few of them are involved in sex determination and differentiation. We report here the existence of Sox genes in the rice field eel, Monopterus albus, and DNA sequence information of the HMG box region of five Sox genes. The Sox1, Sox4 and Sox14 genes do not have introns in the HMG box region. The Sox9 gene and Sox17 gene, which each have an intron in the conserved region, show strong identity at the amino acid level with the corresponding genes of mammals and chickens. Similar structure and identity of the Sox9 and Sox17 genes among mammals, chickens and fish suggest that these genes have evolutionarily conserved roles, potentially including sex determination and differentiation. fish / Sox / cloning / sex determination

Genome duplication, subfunction partitioning, and lineage divergence:Sox9in stickleback and zebrafish

“…Gene prediction analysis using GENSCAN (Burge and Karlin, 1998) showed that each gene comprises three exons and two introns and is predicted to encode translated products of 464 and 477 amino acids that have high sequence similarity to Sox9 . The presumptive HMG domain at the N‐terminus of the protein is well conserved between these predicted peptides and Sox9 co‐orthologs from teleosts (pufferfish, zebrafish, rice eel; Bagheri‐Fam et al, 2001; Chiang et al, 2001; Zhou et al, 2002) and tetrapods (chick, mouse and human; Wright et al, 1993; Wagner et al, 1994; Healy et al, 1999). The C‐termini of the predicted proteins, however, are much less conserved both between the stickleback paralogs and across the other orthologs.…”

“…Both of these sequences fell squarely inside the Sox9 clade with a very high bootstrap value (1,000 of 1,000), showing that they are not orthologs of the closely related Sox8 and Sox10 clades. Furthermore, one stickleback sequence clusters within the Sox9a clade with pufferfish, rice eel, and zebrafish (Chiang et al, 2001; Zhou et al, 2002), whereas the other falls within the Sox9b clade alongside pufferfish and rice eel (Bagheri‐Fam et al, 2001; Zhou et al, 2002) with high bootstrap support (728 of 1000). Because zebrafish sox9b fell as an outgroup to the other teleost Sox9 genes, it was important to be sure it was not a Sox8 , Sox9 , or Sox10 ; therefore, we identified a zebrafish sox8 gene as EST fi23c10 (AW153579) isolated in the Washington University Zebrafish EST Project, and mapped it to LG3 in a region with conserved synteny with human chromosome Hsa16p13.3, the location of human SOX8 (data not shown).…”

Expression of SOX3 and SOX9 Genes in Gonads of Blue Gourami

“…Similar structure and identity of SOX9 and SOX17 genes in mammals, chickens and fish suggest that these genes have evolutionarily conserved roles, potentially including sex determination and differentiation [31]. Based on the current study, we suggested that SOX9 genes were involved in spermatogenesis.…”

Genome-wide analysis of brain and gonad transcripts reveals changes of key sex reversal-related genes expression and signaling pathways in three stages of Monopterus albus

“…The molecular mechanism underlies this special biological process draws many researchers’ attention, and studies showed that several sex differentiation and maturation related genes were involved. Two homologous genes, sox9 and sox17 , were identified in the rice field eel, which showed similar structures and high identities comparing to mammals, indicating evolutionarily conserved roles in sex determination and differentiation [ 23 ], and this speculation was supported by subsequent experimental analysis [ 24 , 25 ]. The c-Jun N-terminal kinases (JNKs), a member from the mitogen-activated protein kinase family, displayed a distinct expression pattern, with a high expression level in ovary, then kept dropping down during the sex transformation [ 26 ].…”