Characterization of Maternal Antigen That Embryos Require (MATER/NLRP5) Gene and Protein in Pig Somatic Tissues and Germ Cells

Abstract

Abstract. Maternal effect genes produce mRNA or proteins that accumulate in the egg during oogenesis and control the developmental program until embryonic genome activation takes place. NLRP5 (NLR family, Pyrin domain containing 5), also called MATER (Maternal Antigen That Embryos Require) is one of the genes required for normal early embryonic development, although its precise function remains to be elucidated. The aim of the present study was to analyze the NLRP5 gene expression pattern and protein distribution in somatic tissues and germ cells in the pig. Reverse transcription was performed on mRNA from germinal vescicle (GV) oocytes and total RNA from spermatozoa and tissues from different organs. The transcript for NLRP5 gene was identified only in ovaries and oocytes. The presence of NLRP5 protein was detected only in ovaries by western blot analysis and immunohistochemistry. Key words: Maternal effect genes, NLR family, Pyrin domain containing 5 (NLRP5), Oocytes, Pig (J. Reprod. Dev. 56: [41][42][43][44][45][46][47][48] 2010) ver the past few years, a number of mammalian genes predominantly or exclusively expressed in germ cells have been discovered. Functional studies have reported the essential role of these genes during gametogenesis, folliculogenesis and early embryonic development [1][2][3][4][5][6][7]. NLRP5 (NLR, pyrin domain containing5), also called MATER (Maternal Antigen That Embryos Require), is one of these genes. However, its precise function remains to be elucidated, although the transcription patterns may suggest a role in embryonic genome activation.Maternal mRNAs accumulated in the oocyte have a crucial role for successful embryo development before activation of the embryonic genome (EGA) [3], and some of them are also required for embryo development after EGA and implantation. These genes, which are called maternal effect genes and which include NLRP5, Zygotic Arrest 1 (Zar1) [8,9], Stella [10,11] and Nucleoplasmin 2 (Npm2) [12], are all required for normal embryonic development beyond the 1-and 2-cell stage in mice [13,14]. Knock-out of these genes leads to incapacity of the embryo to develop beyond the 2-cell stage [15].Developmental block in embryos produced in vitro remains the main problem in assisted reproduction of farm animals, particularly in cattle and pigs. An increasing amount of data indicates that the embryonic genome activation is crucial for the success of preimplantation embryo development [16]. To ensure maternal-embryo transition (MET) of gene expression, oocytes have to reach a sufficiently advanced level of developmental competence during differentiation and maturation [17][18][19]. Maternally expressed genes are implicated in this process, and some of them are associated with developmental competence [20,21]. In domestic species, MET occurs at the 4-16-cell stage [22], a stage in which enough biological material is available to study the fate of maternal mRNAs and their action in regulating embryo cleavages. Studying these genes in farm animals provides a model ...

Nlrp2, a Maternal Effect Gene Required for Early Embryonic Development in the Mouse

“…Nlrp5 ( NLRP5 ) transcripts are detected in the ovary in the mouse [3], [20], bovine [53], [58], [59], pig [60], rhesus macaque monkeys [28], [48] and humans [61]. Moreover it has been demonstrated that Nlrp5 plays key roles in early embryo development in the mouse [3] and rhesus macaque monkeys [28].…”

The subcortical maternal complex: multiple functions for one biological structure?

“…Mater, Floped, and Tle6 expression was observed in oocytes as early as the primary follicle stage [10,17,18]. Comparative studies showed the expression of the genes in several mammalian species, with a moderate degree of sequence conservation, suggesting the potential existence of the complex in all mammals (Table 1) [19][20][21][22].…”

“…n.a. [22] T demonstrated existence of the transcript, P demonstrated existence of the protein, yes the SCMC was visualized in oocytes or embryos, n.a. data not available…”

Major Components in Limiting Litter Size

“…AGO2 is involved in the destruction of maternally inherited transcripts and activation of zygotic gene expression; knockout female for this factor is infertile because embryos fail to undergo the first cleavage [73,74]. Moreover, embryos from MATER, ZAR1, PADI6, and SEBOX knockout females do not develop beyond the 2-cell stage embryo [75][76][77][78][79][80][81][82], and embryos lacking SMARCA4, DNMT1, DNMT3A, TET, and KLF4 are unable to reach the 8-cell stage [83][84][85][86][87][88][89][90][91]. BCLXL, HDAC1, and C-MYC exhibit maximum expression in 8-cell rabbit embryos coinciding with start of ZGA [90].…”