Distinct expression and localization of the type II diacylglycerol kinase isozymes ¿, ¿ and ¿ in the mouse reproductive organs (BMC Developmental Biology)

Background: We have revealed that the type II diacylglycerol kinases (DGKs) ?, ? and ? were expressed in the testis and ovary. However, these enzymes? functions in the reproductive organs remain unknown. Results: In this study, we first identified the expression sites of type II DGKs in the mouse reproductive organs in detail. Reverse transcription-polymerase chain reaction and Western blotting confirmed that DGK?2 (splicing variant 2) but not DGK?1 (splicing variant 1) and DGK? were expressed in the testis, ovary and uterus. DGK?1 (splicing variant 1) but not DGK?2 (splicing variant 2) was strongly detected in the ovary and uterus. Interestingly, we found that a new alternative splicing product of the DGK? gene, DGK?3, which lacks exon 26 encoding 31 amino acid residues, was expressed only in the testis. Moreover, we investigated the distribution of type II DGKs in the testis, ovary and uterus through in situ hybridization. DGK?2 was distributed in the primary spermatocytes of the testis and ovarian follicles. DGK?1 was distributed in the oviductal epithelium of the ovary and the luminal epithelium of the uterus. Intriguingly, DGK?3 was strongly expressed in the secondary spermatocytes and round spermatids of the testis. DGK? was distributed in the primary and secondary spermatocyte of the testis. Conclusion: These results indicate that the expression patterns of the type II DGK isoforms ?2, ?1, ?3 and ? differ from each other, suggesting that these DGK isoforms play specific roles in distinct compartments and developmental stages of the reproductive organs, especially in the processes of spermatogenesis and oocyte maturation.