Anti-NLRP5 (aa 399-513) polyclonal antibody

Initial cell lineages that presage the inner cell mass and extra-embryonic trophectoderm are established when eight blastomeres compact to form polarized morulae in preimplantation mouse development. FILIA has been identified as a binding partner to MATER (maternal antigen that embryos require; also known as NLRP5), which is encoded by a maternal effect gene. Products of each gene are detected in growing oocytes and, although transcripts are degraded before fertilization, the cognate proteins persist in early blastocysts. The two proteins co-localize to the cytocortex of ovulated eggs, where the stability of FILIA is dependent on the presence of MATER. After fertilization, FILIA-MATER complexes become asymmetrically restricted in the apical cytocortex of two-cell embryos due to their absence in regions of cell-cell contact. This asymmetry is reversible upon disaggregation of blastomeres of the two- and four-cell embryo. Each protein persists in cells of the preimplantation embryo, but the continuous cell-cell contact of 'inner' cells of the morulae seemingly precludes formation of the subcortical FILIA-MATER complex and results in cell populations that are marked by its presence ('outer') or absence ('inner'). Thus, the FILIA-MATER complex provides a molecular marker of embryonic cell lineages, but it remains to be determined if the molecular asymmetry established after the first cell division plays a role in cell fate determinations in the early mouse embryo.

WNT4 is required for normal ovarian follicle development and female fertility in mice, but how its signal is transduced remains unknown. Fzd1 encodes a WNT receptor whose expression is markedly induced in both mural granulosa cells and cumulus cells during the preovulatory period, in a manner similar to Wnt4. To study the physiological roles of FZD1 in ovarian physiology and to determine whether it serves as receptor for WNT4, Fzd1-null mice were created by gene targeting. Whereas rare Fzd1(-/-) females were sterile because of uterine fibrosis and ovarian tubulostromal hyperplasia, most were subfertile, producing approximate to 1 fewer pup per litter on average relative to controls. Unlike WNT4-deficient mice, ovaries from Fzd1(-/-) mice had normal weights, numbers of follicles, steroid hormone production, and WNT4 target gene expression levels. Microarray analyses of granulosa cells from periovulatory follicles revealed few genes whose expression was altered in Fzd1(-/-) mice. However, gene expression analyses of cumulusoocyte complexes ( COCs) revealed a blunted response of both oocyte ( Zp3, Dppa3, Nlrp5, and Bmp15) and cumulus ( Btc, Ptgs2, Sema3a, Ptx3, Il6, Nts, Alcam, and Cspg2) genes to the ovulatory signal, whereas the expression of these genes was not altered in WNT4-deficient COCs from Wnt4(tm1.1Boer/tm1.1Boer); Tg ( CYP19A1-cre)1Jri mice. Despite altered gene expression, cumulus expansion appeared normal in Fzd1(-/-) COCs both in vitro and in vivo. Together, these results indicate that Fzd1 is required for normal female fertility and may act in part to regulate oocyte maturation and cumulus cell function, but it is unlikely to function as the sole ovarian WNT4 receptor.