[Cloning and expression of a novel mouse testis gene TSEG-2].

Objective: To clone the mouse testis specific gene TSEG-2 via a bioinformatic approach.

Methods: The expressed sequence tags (EST) in the normal mouse testis were obtained from the online EST database ZooDDD. Their highly homologous EST sequences were retrieved through the dbEST database to construct contigs and spliced with the biomedical software Biolign. The corresponding exons and introns within the genome sequences were predicted with the software GeneScan. Primers were designed according to the open reading frame. RT-PCR was applied in cloning the cDNA of the novel gene from the mouse testis tissue and analyzing its expression patterns in the undescended testis and various organ tissues as well as in different developmental stages of the mouse testis. The sequencing results of TSEG-2 underwent bioinformatic analyses.

Results: The novel mouse testis gene TSEG-2 was successfully cloned, with full-length sequence of 451 bp. The open reading frame was 267 bp, coding a protein of 88 amino acid residues, and demonstrated to be correct by RT-PCR. The expression of TSEG-2 was high in the mouse testis, regular in the testis cDNA samples of different postnatal days, and down-regulated in the cryptorchidism model. No obvious homology with other mouse cDNA was found for TSEG-2. The GenBank accession number EU079025 was achieved. Function prediction showed that mouse TSEG-2 was probably a soluble non-secretary protein located at chromosome 15qE3, or a nucleoprotein with 2 phosphorylation sites of protein kinase C (PKC) and 1 of casein kinase II (CK2).

Conclusion: A novel mouse testis specific gene TSEG-2 was successfully cloned, which could be down-regulated by cryptorchidism-inducible 17-beta estradiol. This has prepared the ground for further researches on the biological function and expression regulation of TSEG-2.