Spindlin1 alters the metaphase to anaphase transition in meiosis I through regulation of BUB3 expression in porcine oocytes. Choi JW et al. (2018) Spindlin 1 (SPIN1), which contains Tudor-like domains, regulates maternal transcripts via interaction with a messenger RNA (mRNA)-binding protein. SPIN1 is involved in tumorigenesis in somatic cells and is highly expressed in cancer cells. Nevertheless, the role of SPIN1 in porcine oocyte maturation remains totally unknown. To explore the function of SPIN1 in porcine oocyte maturation, knockdown, and overexpression techniques were used. SPIN1 mRNA was identified in maternal stages ranging from GV to MII. SPIN1 was localized in the cytoplasm and to chromosomes during meiosis. SPIN1 knockdown accelerated first polar body extrusion. Oocytes with overexpressed SPIN1 were arrested at the MI stage. SPIN1 depletion caused meiotic spindle defects and chromosome instability. The BUB3 signal was investigated, confirming that SPIN1 affects the stability of Bub3 mRNA as well as BUB3 expression. Further, overexpression of SPIN1 inhibited the degradation and regulation of G2/mitotic-specific cyclin-B1. In summation, SPIN1 regulates the meiotic cell cycle by modulating the activation of the spindle assembly checkpoint.//////////////////
Spindlin 1 is essential for metaphase II stage maintenance and chromosomal stability in porcine oocytes. Choi JW et al. (2017) What is the function of Spindlin 1 (Spin1) in metaphase II stage oocytes in pigs? Depletion of Spin1 induces spontaneous oocyte activation and overexpression of Spin1 causes multinuclear formation through induction of DNA damage in porcine oocytes. Little is known about the function of Spin1 in oocytes and embryos. In mouse oocytes, Spin1 is specifically expressed during gametogenesis and is essential for meiotic resumption. In somatic cells, Spin1 promotes cancer cell proliferation and activates WNT/T-cell factor signaling. After knockdown (KD) or overexpression of Spin1 in porcine MII-stage oocytes, MII maintenance was checked following additional culture for 24 h. Investigated parthenotes were cultured up to the four cell (72 h) or blastocyst (7 days) stages. Spin1 was knocked down in porcine oocytes and embryos via microinjection of pig Spin1-targeting siRNA. For Spin1 overexpression, porcine Spin1-eGFP cRNA was generated. Additionally, for rescue experiments, cRNA encoding siRNA-resistant mouse Spin1 was added to the pig Spin1-targeting siRNA. For the overexpression and rescue experiments, microinjection and culture were performed using the same methods as the KD experiments. KD of Spin1 in MII-stage porcine oocytes reduced metaphase-promoting factor and mitogen-activated protein kinase activities, resulting in spontaneous pronuclear formation without calcium activation. However, the DNA damage response was triggered by Spin1 overexpression, generating the checkpoint protein γH2A.X. Furthermore, Spin1 overexpression blocked metaphase-anaphase transition and led to multinucleation in oocytes and embryos. None. This study is based on in vitro investigations with abnormal expression levels of Spin1. This may or may not accurately reflect the situation in vivo. Spin1 is essential to maintain MII arrest, but a high level of Spin1 induces DNA damage in oocytes and embryos. Thus, a system to accurately regulate Spin1 expression operates in porcine MII-stage oocytes and embryos. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2015R1D1A1A01057629). The authors declare no competing financial interests.//////////////////
Proteomic profiling of murine oocyte maturation. Vitale AM et al. In an effort to better understand oocyte function, we utilized two-dimensional (2D) electrophoresis and mass spectrometry to identify proteins that are differentially expressed during murine oocyte maturation. Proteins from 500 germinal vesicle (GV) and metaphase II-(MII) arrested oocytes were extracted, resolved on 2D electrophoretic gels, and stained with silver. Analysis of the gels indicated that 12 proteins appeared to be differentially expressed between the GV and MII stage. These proteins were then cored from the 2D gels and identified by mass spectrometry as: transforming acidic coiled-coil protein 3 (TACC3), heat shock protein 105 (HSP105), programmed cell death six-interacting protein (PDCD6IP), stress-inducible phosphoprotein (STI1), importin alpha2, adenylsuccinate synthase (ADDS), nudix, spindlin, lipocalin, lysozyme, translationally controlled tumor protein (TCTP), and nucleoplasmin 2 (NPM2). Interestingly, PDCD6IP, importin alpha2, spindlin, and NPM2 appear slightly larger in mass and more acidic on the MII oocyte gel compared to the GV oocyte gel, suggesting that they may be post-translationally modified during oocyte maturation. Given NPM2 is an oocyte-restricted protein, we chose to further investigate its properties during oocyte maturation and preimplantation development. Real-Time RT-PCR showed that NPM2 mRNA levels rapidly decline at fertilization. Indirect immunofluorescence analysis showed that, with the exception of cortical localization in MII-arrested oocytes, NPM2 is localized to the nucleus of both GV stage oocytes and all stages of preimplantation embryos. We then performed one-dimensional (1D) western blot analysis of mouse oocytes and preimplantation embryos and found that, as implicated by the 2D gel comparison, NPM2 undergoes a phosphatase-sensitive electrophoretic mobility shift during the GV to MII transition. The slower migrating NPM2 form is also present in pronuclear embryos but by the two-cell stage, the majority of NPM2 exists as the faster migrating form, which persists to the blastocyst stage. Mol. Reprod. Dev. (c) 2006 Wiley-Liss, Inc.
Expression regulated by
Comment
Ovarian localization
Oocyte, Ovarian tumor
Comment
Allegro: Analyzing expression and sequence in concert to discover regulatory programs. Halperin Y et al. A major goal of system biology is the characterization of transcription factors and microRNAs (miRNAs) and the transcriptional programs they regulate. We present Allegro, a method for de-novo discovery of cis-regulatory transcriptional programs through joint analysis of genome-wide expression data and promoter or 3' UTR sequences. The algorithm uses a novel log-likelihood-based, non-parametric model to describe the expression pattern shared by a group of co-regulated genes. We show that Allegro is more accurate and sensitive than existing techniques, and can simultaneously analyze multiple expression datasets with more than 100 conditions. We apply Allegro on datasets from several species and report on the transcriptional modules it uncovers. Our analysis reveals a novel motif over-represented in the promoters of genes highly expressed in murine oocytes. The present gene id highly expressed in the oocyte and has a unique promoter motif.
Expression, purification, crystallization and preliminary x-ray analysis of human spindlin1, an ovarian cancer-related protein. Jiang F et al. Human spindlin1 is a newly screened and identified gene product related to ovarian carcinomas and is highly homologous to mouse spindlin. It is an abundant maternal transcript expressed in the mouse during the transition from oocyte to embryo. Here, the recombinant human spindlin1 has been overexpressed in Escherichia coli BL21, purified and crystallized using the hanging-drop vapour-diffusion method. Crystals diffracting to 2.25 A resolution were obtained using ammonium sulfate as precipitant. The crystals belong to the space group P2(1)2(1)2(1), with unit-cell parameters a =40.7 A, b =84.4 A, c =136.4 A, alpha=beta=gamma=90 degrees . Assuming two molecules per asymmetric unit, the solvent content is calculated to be 42.4%.
Follicle stages
Comment
Genomewide discovery and classification of candidate ovarian fertility genes in the mouse. Gallardo TD et al. Female infertility syndromes are among the most prevalent chronic health disorders in women, but their genetic basis remains unknown because of uncertainty regarding the number and identity of ovarian factors controlling the assembly, preservation, and maturation of ovarian follicles. To systematically discover ovarian fertility genes en masse, we employed a mouse model (Foxo3) in which follicles are assembled normally but then undergo synchronous activation. We developed a microarray-based approach for the systematic discovery of tissue-specific genes and, by applying it to Foxo3 ovaries and other samples, defined a surprisingly large set of ovarian factors (n = 348, approximately 1% of the mouse genome). This set included the vast majority of known ovarian factors, 44% of which when mutated produce female sterility phenotypes, but most were novel. Comparative profiling of other tissues, including microdissected oocytes and somatic cells, revealed distinct gene classes and provided new insights into oogenesis and ovarian function, demonstrating the utility of our approach for tissue-specific gene discovery. This study will thus facilitate comprehensive analyses of follicle development, ovarian function, and female infertility. This is an oocyte-specific gene.
Phenotypes
Mutations
1 mutations
Species: mouse
Mutation name: None
type: null mutation fertility: infertile - ovarian defect Comment: A Tudor Domain Protein SPINDLIN1 Interacts with the mRNA-Binding Protein SERBP1 and Is Involved in Mouse Oocyte Meiotic Resumption. Chew TG 2013 et al.
Mammalian oocytes are arrested at prophase I of meiosis, and resume meiosis prior to ovulation. Coordination of meiotic arrest and resumption is partly dependent on the post-transcriptional regulation of maternal transcripts. Here, we report that, SPINDLIN1 (SPIN1), a maternal protein containing Tudor-like domains, interacts with a known mRNA-binding protein SERBP1, and is involved in regulating maternal transcripts to control meiotic resumption. Mouse oocytes deficient for Spin1 undergo normal folliculogenesis, but are defective in resuming meiosis. SPIN1, via its Tudor-like domain, forms a ribonucleoprotein complex with SERBP1, and regulating mRNA stability and/or translation. The mRNA for the cAMP-degrading enzyme, PDE3A, is reduced in Spin1 mutant oocytes, possibly contributing to meiotic arrest. Our study demonstrates that Spin1 regulates maternal transcripts post-transcriptionally and is involved in meiotic resumption.
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