Cloning and characterization of full length of a novel zebrafish gene Zsrg abundantly expressed in the germline stem cells

Characterization of mouse synaptic vesicle-2-associated protein (Msvop) specifically expressed in the mouse central nervous system

In this study, we identified and characterized a mouse brain-enriched unigene (msvop) after performing digital differential display. Msvop was the mouse ortholog of Xenopus synaptic vesicle-2-associated protein (svop), the molecular characteristics of which were unknown. The 3125-bp full-length cDNA encoded a 548-aa protein of approximately 60 kDa. A strong promoter element was found in the -200 to -100 bp region in both NG108-15 and HEK293 cells. RT-PCR and in situ hybridization analysis confirmed that msvop was strictly expressed in the mouse central nervous system. In adult brains, msvop was highly expressed in the hippocampus and cerebellum. When the gene was transfected into HEK293 cells in a GFP fusion vector, the protein was specifically localized in the cytosol. These results indicate that msvop is a central nervous system-specific gene and could be utilized for elucidating gene regulation in neuronal cells.

Characterization of a novel mouse brain gene (mbu-1) identified by digital differential display

Using in silico approaches, we cloned a novel mouse gene (mbu-1) that was strictly expressed in the central nervous system. mbu-1 was first identified as an EST after carrying out digital differential display for unigene libraries from various mouse tissues. The full-length cDNA sequence was obtained by extending the ends of EST by RACE. The cDNA sequence was 2611 bp long and contained an ORF of 597 AA. A positive cis-acting region was found in the neuroblastomaxglioma hybrid, NG108-15, and in human embryonic kidney HEK293 cell lines. RT-PCR and in situ hybridization analysis showed that the mbu-1 gene was only expressed in the brain and spinal cord during the embryonic stages, and throughout all regions of the adult brain, showing higher levels in the hippocampus and hypothalamus.

Identification and characterization of TSAP, a novel gene specifically expressed in testis during spermatogenesis

Through in silico screens, we have identified many previously uncharacterized genes that display similar expression patterns as the mouse Dazl gene, a germ line-specific marker. Here, we report the identification and characterization of one of these novel genes. TSAP gene encodes a protein with 350 amino acids and contains five ankyrin repeats and a PEST sequence motif. Furthermore, we have generated an anti-TSAP antibody and have used three different approaches (RT-PCR, in situ hybridization, and immunohistochemistry) to investigate the expression profiles of TSAP mRNAs and proteins. TSAP is specifically expressed in testis, but not in other tissues such as ovary. Within the testis, TSAP is detected 10 days after birth and is mainly expressed in spermatocytes (ST) and later stage of germ cells, but not in spermatogonia (SG) or sertoli cells. Therefore, TSAP protein likely plays a role in spermatogenesis.

Cloning and characterization of a rice field eel vasa-like gene cDNA and its expression in gonads during natural sex transformation

The vasa (vas)-related gene encodes an RNA helicase protein member of the DEAD-box family and plays key roles in germ-cell formation in higher metazoans. Using degenerate PCR and RACE, we cloned the vasa gene of the rice field eel (Monopterus albus), which is homologous to the Drosophila vasa gene. We named it ma-vas (Monopterus albus vas). Ma-vas encodes a protein of 618 amino acids, which contains all of the known characteristics of vasa homologs. RT-PCR analysis revealed that ma-vas was exclusively expressed in the gonads of the female, intersex, and male. During gonadal natural sex reversal, ma-vas is expressed in oocytes at all stages of oogenesis, in degenerating oocytes of ovotestis, and in spermatogonia and spermatocytes at early stages. The vasa positive signal was also observed in the peripheral layer of late ovary. It was not found, however, in that layer of the testis. Alkaline phosphatase (AKP) staining on the ovary and testis also indicated that some cells had differentiational potential in the peripheral layer of the ovary, suggesting that spermatogonia might arise from cells with AKP and vasa-positive staining in the peripheral layer of the female gonad.

Molecular cloning of a novel gene ZAhi-1 and its expression analysis during zebrafish gametogenesis

Proto-oncogen Ahi-1 is closely related to a lot of human and mouse diseases. Ahi-1 mutation will lead to leukemia in mice and Joubert syndrome in human beings. We have cloned the full cDNA sequence of Ahi-1 homologous in zebrafish, and RT-PCR results of ZAhi-1 in different tissues reveal that ZAhi-1 expressed highest in the mature gonad. In situ hybridization results of zebrafish gonad show that ZAhi-1 only expressed in the early stages' gamete cells. RT-PCR analyses of mouse Ahi-1 in different stages of spermatogenesis have been done according to the published Ahi-1 sequence, and the findings reveal that Ahi-1 is expressed in gamete of pachytene stage. It can then be safely concluded that Ahi-1 might take place in the spermatocyte from the early pachytene stage to the late pachytene stage.

PSM2, a novel protein similar to MCAF2, is involved in the mouse embryonic and adult male gonad development

By screening RIKEN database, we obtained a mouse ovary and uterus derived clone (RIKEN clone ID: 5031403I04). Multiple tissues expression analysis revealed that the clone was specifically expressed in ovary and to a higher extent in testis. It is expressed in early mouse embryo, especially in the embryonic gonad from 11.5 dpc (days post coitus). Furthermore, it is also expressed continuously from newborn testis to adult. Using testis sections in situ hybridization, we found the mRNA was localized to spermatogonia, round spermatids and mainly to spermatocytes. We cloned the cDNA from mouse testis. The gene consists of 10 exons spanning approximately 48 kb on mouse chromosome 16. The cDNA encodes a putative nuclear protein of 319 amino acids containing a coiled-coil motif. The deduced protein has high similarity with human MCAF2 (MBD1-containing chromatin-associated factor 2), so we termed it as PSM2 (protein similar to MCAF2) in this article. We therefore hypothesized that PSM2 might interact with some important partners by the conserved domain and be involved in the transcription modulation during gonad development.

Two novel transcripts encoding two Ankyrin repeat containing proteins have preponderant expression during the mouse spermatogenesis

The clone 4921537P18 expressed preponderantly in mouse testis was identified by screening the Riken cDNA database, and two new full-length isoforms of this clone, which were named gsarp1 (Gonad Specific Ankyrin Repeat (ANK) Protein 1) and gsarp2, were found and isolated from mouse testis in the course of the research. Both of the GSARP1 and GSARP2 contain an ANK region circular composed by seven ANKs, and their structural feature is very similar to that of the IkappaB family proteins, while IkappaB proteins associate with the transcription factor NF-kappaB via their ANKs in the NF-kappaB pathway. We investigated the expression pattern at the mRNA level by Reverse transcription PCR. The gsarp1 has high expression level in mouse testis, while has low expression level in the ovary, and the gsarp2 is only expressed in mouse testis. The gsarp1 and gsarp2 begin to be detected at the early and later pachytene stage of meiosis separately, while both have high-expression level at the stage of MI and MII. The result of in situ hybridization reveals that the gsarp1 is primarily expressed in spermatocytes, while gsarp2 is expressed in spermatocytes and spermatids. In view of the structural feature and expression pattern of the GSARP1 and GSARP2, we speculate that they may play a certain role in a signal pathway of meiosis.

Zebrafish z-otu, a novel Otu and Tudor domain-containing gene, is expressed in early stages of oogenesis and embryogenesis

Several studies have suggested that Otu domain had de-ubiquitinating activity and Tudor domain was important for the formation of germ cells. Here, we reported a novel zebrafish ovary-specific gene containing Otu and Tudor domain, z-otu, which was expressed at stages I-III oocytes and embryonic stages from zygotes to early blastula during embryonic cells maintained their totipotency. Therefore, z-otu might link the ubiquitin signaling pathway to early oogenesis and maintaining the totipotency of embryonic cell.