Differential screening and characterization analysis of the egg envelope glycoprotein ZP3 cDNAs between gynogenetic and gonochoristic crucian carp

Abstract

Gynogenetic silver crucian carp, Carassius auratus gibelio, is an intriguing model system. In the present work, a systemic study has been initiated by introducing suppression subtractive hybridization technique into this model system to identify the differentially expressed genes in oocytes between gynogenetic silver crucian carp and its closely related gonochoristic color crucian carp. Five differential cDNA fragments were identified from the preliminary screening, and two of them are ZP3 homologues. Moreover, the full length ZP3 cDNAs were cloned from their oocyte cDNA libraries. The length of ZP3 cDNAs were 1378 bp for gyno-carp and 1367 bp for gono-carp, and they can be translated into proteins with 435 amino acids. Obvious differences are not only in the composition of amino acids, but also in the number of potential Olinked oligosaccharide sites. In addition, gyno-carp ZP3 amino acid sequence has an unexpected higher identity value with common carp (83.5%) than that with the closely related gono-carp (74.7%). The unique homology may be originated from the ancient hybridization. Northern blot analysis confirmed that expression of the ZP3 gene occurred exclusively in the oocytes. Because O-linked oligosaccharides on ZP3 have been demonstrated to play very important roles in fertilization, it is suggested that the extra O-linked glycosylation sites may be related to the unique sperm-egg recognition mechanism in gynogenesis.

Identification of a putative oocyte-specific small nuclear ribonucleoprotein polypeptide C in gibel carp

“…It has been known that numerous oocyte-specifically expressed genes play key roles in oogenesis, fertilization and early embryonic development. Recently, subtractive hybridization has been widely used to isolate the oocyte-specific genes in vertebrates including fish (Kanamori, 2000;Xie et al, 2001;Fan et al, 2001), amphibian (Vallee et al, 2005) and mammals (Paillisson et al, 2005;Pennetier et al, 2005;Vallee et al, 2005), and some novel oocyte-specific genes have been screened and identified.…”

“…Gibel carp (Carassius auratus gibelio), as a unique gynogenetic fish distributed in China (Jiang et al, 1983;Zhou et al, 2000a,b;Zhou and Gui, 2002), has been used as an intriguing study model for understanding regulatory mechanisms of oocyte maturation, fertilization and early embryogenesis (Fan et al, 2001;Xie et al, 2001Xie et al, , 2003. Some oocyte-specifically expressed genes, such as ZP3 (Fan et al, 2001;Chen et al, 2005), SNX , C-type lectin (Dong et al, 2004), CaOC1q-like factor (Chen and Gui, 2004), and CagSpindlin (Wang et al, 2005), have been identified and characterized.…”

“…Some oocyte-specifically expressed genes, such as ZP3 (Fan et al, 2001;Chen et al, 2005), SNX , C-type lectin (Dong et al, 2004), CaOC1q-like factor (Chen and Gui, 2004), and CagSpindlin (Wang et al, 2005), have been identified and characterized. A full-length cDNA encoding 66 aa peptide, named YA2 (GenBank accession number AF315727), was also cloned from the suppression subtractive hybridization cDNA library of gibel carp (Xie et al, 2001).…”

Identical sequences but different expression patterns of Hira gene in gynogenetic and gonochoristic crucian carps

“…At present, the molecular mechanisms underlying the reproductive strategies of gibel carp are poorly understood, making this fish a promising study model for developmental biology (Gui 1996;Zhou et al 2000b;Xie et al 2001Xie et al , 2003. It has been proposed that the reproductive modes of this species may subject to some regulatory factors during oocyte maturation and fertilization (Wang et al 2000;Fan et al 2001;Shi et al 2002).…”

cDNA cloning and characterization of a novel SNX gene differentially expressed in previtellogenic oocytes of gibel carp

“…Recently, artificial propagation experiments, cytological investigation and molecular marker analysis have proved that the gibel carp should have two different reproductive modes, that is, allogynogenetic reproduction and gonochoristic reproduction (Zhou et al, 2000a,b). All these features make the fish a promising study model for evolutionary genetics and developmental biology (Gui, 1996;Zhou et al, 2000b;Fan et al, 2001;Shi et al, 2002;Xie et al, 2001Xie et al, , 2003.…”