Expression patterns of Nlrp9a, Nlrp9b and Nlrp9c during mouse development

The Nlrp gene family contains 20 members in the mouse. Recent studies have demonstrated that these genes play key roles in reproduction. In this study, we investigated the expression patterns of Nlrp9a, Nlrp9b and Nlrp9c in the mouse. In 2-week-old mouse tissues, Nlrp9a, Nlrp9b and Nlrp9c were all strikingly expressed in the ovary, while the transcripts of Nlrp9b and Nlrp9c were also detected in other tissues. The transcripts of Nlrp9a, Nlrp9b and Nlrp9c were restricted to the oocytes and declined with oocyte aging within the ovary. Furthermore, Nlrp9a, Nlrp9b and Nlrp9c transcripts presented evidence for the exclusive maternal origin, which were presented in oocytes and zygotes, immediately downregulated and not detected after the 2-cell stage during preimplantation development. In addition, Nlrp9a and Nlrp9c transcripts were not detected in other cells except for oocytes. Nevertheless, Nlrp9b expression was detected in oocytes, as well as in D3 ES and F9 ES. These results indicate that Nlrp9a, Nlrp9b and Nlrp9c display specific or preferential oocyte expression patterns and may play critical role in oogenesis and/or preimplantation embryo development in the mouse.