Identification of oocyte-selective NLRP genes in rhesus macaque monkeys (Macaca mulatta).

Oocyte-selective genes control multiple aspects of female gamete development and preimplantation embryogenesis. Several key oocyte-selective factors have been identified in mice recently; however, these factors are not well documented in more advanced species such as nonhuman primates. One of such oocyte-selective factors is NLRP5 (NLR family, Pyrin domain containing 5), also known as Maternal Antigen That Embryos Require (MATER), which is required for preimplantation embryo development beyond the 2-cell stage in mice. Human NLRP family contains 14 members. We identified 14 NLRP gene homologues and examined their spatial and temporal expression in rhesus macaque monkeys (Macaca mulatta). While all 14 NLRP genes are detectable in the macaque gonad, eight of them (NLRP2, 4, 5, 8, 9, 11, 13, and 14) are specifically or preferentially expressed in the ovary. In situ hybridization elucidated a specific oocyte expression pattern of the eight NLRP genes within the ovary. During the oocyte-to-embryo transition, seven of these oocyte-selective NLRP transcripts (excluding NLPR2) are enriched in maturing oocytes and early preimplantation embryos but diminish upon embryo genome activation, indicating an exclusive maternal origin of these transcripts. Though functionally unknown, the spatial and temporal distribution of these oocyte-selective NLRP genes implies important roles of the NLRP family in oogenesis and early embryo development in nonhuman primates.