Differential expression of annexin V during spermatogenesis in the newt Cynops pyrrhogaster

Abstract

In order to isolate genes whose expression is up-regulated after the initiation of meiosis, we screened a cDNA expression library of newt testes with antiserum against homogenates of testes derived from the spermatogonial and spermatocyte stages. We report the isolation of spermatocyte-specific cDNA clones encoding a newt homologue of the calcium-dependent phospholipid-binding protein, annexin V. Northern blot analysis showed that newt annexin V mRNA was 1.7 kb in length and was expressed strongly in testes, but weakly in other organs. In situ hybridization revealed that the expression of newt annexin mRNA was barely observed in spermatogonia, but increased significantly in leptotene-zygotene primary spermatocytes and reached a maximum level in pachytene spermatocytes and round spermatids. The newt annexin V cDNA predicted a 323-amino acid protein and had a 68% homology to human annexin V. The predicted amino acid sequence contained a conserved 4-fold internal repeat of approximately 70 residues like other annexin proteins. Immunoblot analysis using the monoclonal antibody against newt annexin V showed that the protein was expressed scarcely in spermatogonia but was abundantly expressed in stages from primary spermatocytes to spermatids; this pattern was consistent to that of the mRNA. Immunohistochemical analysis revealed that newt annexin V was localized in the cytoplasm of the spermatogenic cells, but not in somatic cells such as Sertoli cells or pericystic cells. These results indicate that the expression of newt annexin V is up-regulated in the spermatogenic cells after the initiation of meiosis and suggest that newt annexin V plays an important role in spermatogenesis.

Conversion from mitosis to meiosis: Morphology and expression of proliferating cell nuclear antigen (PCNA) and Dmc1 during newt spermatogenesis

“…In the previous study, we have shown that newt annexin V serves as a molecular marker to monitor the differentiation of spermatogonia into primary spermatocytes ( Yamamoto et al 1996 ). However, annexin V mRNA expression starts in primary spermatocytes during the leptotene–zygotene stages, when meiosis has already initiated.…”

Cloning and Expression of a cDNA Encoding a Prolactin Receptor of the Japanese Red-Bellied Newt, Cynops pyrrhogaster

“…Poly(A) + -RNA was prepared from various tissues of adult newts as described above. Northern blot analysis was done as described previously (Yamamoto et al, 1996). Five microgram of poly(A) + -RNA was electrophoresed in a 1% formaldehyde agarose gel and blotted to a nylon-membrane, Hybond(N)+ (Amersham).…”

Low Temperature Promotes Annexin V Expression in Newt Testis

“…Protein extraction and Western blot analysis using a monoclonal antibody against recombinant newt annexin V were performed as described previously (Yamamoto et al ., 1996). Ten micrograms of protein extracted from newt testis were separated by 12% SDS-PAGE, blotted onto PVDF membrane (Millipore), and treated with the anti-newt annexin V monoclonal antibody.…”

“…Previously, we isolated annexin V as a protein differentially expressed during newt spermatogenesis (Yamamoto et al ., 1996). Newt annexin V is abundantly expressed in the cytoplasm of primary spermatocytes and round spermatids.…”