Cloning and characterization of Vasa gene expression pattern in adults of the Lusitanian toadfish Halobatrachus didactylus

Abstract

The Vasa gene is essential for germ cell development in eukaryotes. It encodes a RNA helicase, a member of the DEAD box protein family. Using the RACE method, we cloned the Vasa cDNA of the Lusitanian toadfish Halobatrachus didactylus, and analyzed quantitative and qualitative Vasa expression and its protein immunolocalization. We reported a main product of about 2.4 kb which encodes a protein of 615 amino acids, but other minority Vasa products were also identified by RACE-PCR. This gene is predominantly expressed in the ovaries and testes, although some relatively low extragonadal expression levels have also been identified. In situ hybridization and immunolocalization analysis during gametogenesis in the testes showed that toadfish Vasa mRNA was detected in spermatogonia, spermatocytes and spermatids. However, in the ovaries, Vasa mRNA was detected in early vitellogenic oocytes and in more advanced vitellogenic stages, showing a very weak signal in oogonia, whereas the Vasa protein was evidenced in the cytoplasm of oogonia and previtellogenic oocytes, becoming weaker as the vitellogenic and maturation processes progress. These results suggest that toadfish Vasa homologues can play an important role in gametogenesis and germ cell development, but it could also be functionally implicated in other processes that are not as well known.

Molecular and Physiological Effects of 17α-methyltestosterone on Sex Differentiation of Black Rockfish, Sebastes schlegelii

“…Our study also analyzed vasa gene expression, mainly involved in the migration and differentiation of primordium germ cells in vertebrates, including in teleost [54][55][56]. In males, vasa expression was significantly lower than in females at 140 dpb, aligning with histological observations, indicating a period of accelerated ovarian development in females.…”

Identification and sexually dimorphic expression of vasa isoforms in Dabry′s sturgeon (Acipenser dabryanus), and functional analysis of vasa 3′-untranslated region

“…On the other hand, tissue distribution analysis in immature Dabry's sturgeons revealed that Advasa transcripts were predominantly found in the ovary and testis, and also detected in the liver, intestines, spleen, kidney, heart and brain. Low expression levels of vasa in the extragonadal tissues was described in rainbow trout (Yoshizaki et al 2000), European sea bass (Blazquez et al 2011), Senegalese sole (Pacchiarini et al 2013), tongue sole and Lusitanian toadfish (Ubeda-Manzanaro et al 2014). This was ascribed to Vasa helicase activity referring to translational regulation of mRNAs involved in the specification and differentiation of other tissue-specific cell types (Ikenishi and Tanaka 2000).…”

Characterization of ddx4 and dnd Homologs in Snakeskin Gourami (Trichopodus pectoralis) and Their Expression Levels during Larval Development and in Gonads of Males and Females

“…Using RT-PCR and in situ hybridization, we demonstrated that ddx4 and dnd1 are specifically expressed in the gonads, particularly in germ cells. Similar specific expressions of ddx4 mRNA in the gonads have been demonstrated in rainbow trout [ 50 ], medaka [ 51 ], tilapia [ 30 ], gibel carp [ 52 ], rice field eel [ 53 ], Pacific bluefin tuna [ 54 ], carp [ 55 ], catfish [ 18 ], European seabass [ 56 ], rare minnow [ 57 ], Atlantic cod [ 58 ], Korean rockfish [ 59 ], Solea senegalensis [ 60 ], toadfish [ 61 ], Japanese flounder [ 20 ], brown-marbled grouper [ 31 ], striped catfish [ 7 ], and Mekong giant catfish [ 62 ]. Coincidentally, the specific expression of dnd1 in testes and ovaries was revealed in zebrafish [ 15 ], medaka [ 29 ], rare minnow [ 63 ], gibel carp [ 13 ], tambaqui [ 64 ], Atlantic salmon [ 65 ], and starry flounder [ 21 ].…”