Ste20‐like kinase activity promotes meiotic resumption and spindle microtubule stability in mouse oocytes

Abstract

Ste20-like kinase (SLK) is involved in cell proliferation and migration in somatic cells.This study aims to explore SLK expression and function in mouse oocyte meiosis.Western blot, immunofluorescence, Co-immunoprecipitation, drug treatment, cRNA construct and in vitro transcription, microinjection of morpholino oilgo (MO) and cRNA were performed in oocytes. High and stable protein expression of SLK was detected in mouse oocyte meiosis, with dynamic distribution in the nucleus, chromosomes and spindle apparatus. SLK phosphorylation emerges around meiotic resumption and reaches a peak during metaphase I (MI) and metaphase II. SLK knockdown with MO or expression of kinase-dead SLK K63R dramatically delays meiotic resumption due to sequentially suppressed phosphorylation of Polo-like kinase 1 (Plk1) and cell division cycle 25C (CDC25C) and dephosphorylation of cyclin-dependent kinase 1 (CDK1). SLK depletion promotes ubiquitination-mediated degradation of paxillin, an antagonist to α-tubulin deacetylation, and thus destroys spindle assembly and chromosome alignment; these phenotypes can be substantially rescued by exogenous expression of SLK kinase active fragment. Additionally, exogenous SLK effectively promotes meiotic progression and spindle assembly in aging oocytes with reduced SLK. Collectively, this study reveals SLK is required for meiotic resumption and spindle assembly in mouse oocyte meiosis. | INTRODUCTIONMammalian oocytes of high-developmental-competence are required for successful fertilization and subsequent embryo development, which initiates a new life. 1 Fully-grown oocytes are arrested at the diplotene stage of the first meiotic prophase, known as the germinal vesicle (GV) stage. 2 Following the ovulatory luteinizing hormone (LH) surge, the resumption of meiosis occurs with the signature of germinal vesicle breakdown (GVBD) followed by chromatin condensation. 3,4 During the prometaphase of meiosis I (Pro-MI), the acentrosomal spindle is assembled along with the congression of condensed chromosomes. 5 Upon all chromosomes are correctly aligned and stably attached by microtubules from spindle poles at metaphase I (MI), the meiotic cell cycle moves to anaphase I (AI), during which the homologous chromosomes are segregated, and the first polar body (PB1) is discharged. 6 The orderly meiotic progression is essential for the high-quality oocytes and, furthermore, female reproductive health. 1,7 The abnormal oocyte meiotic process leads to embryo aneuploidy, a significant cause of infertility, abortion and fetal deformity. 7 The fully-grown oocytes accumulate large quantities of mRNAs and proteins and stop de novo mRNA transcription at the GV stage, so the meiotic progression is regulated by a complex and cascading

Iron accumulation in ovarian microenvironment damages the local redox balance and oocyte quality in aging mice

“…The slides were air-dried at room temperature and stored at −20 °C before use. Prior to 1 h blocking in 1 % BSA, slides were immersed in adequate PBS to wash off salts mixed in the chromosome samples [ 28 , 29 ]. The samples were immune-stained with human centromere auto serum (CREST) (1:100; 90C-CS1058, Fitzgerald) and counterstained with mounting medium containing DAPI, then analyzed with ZEISS microscopic system and Image J software as stated above.…”

Association analysis of polymorphisms in SLK, ARHGEF9, WWC2, GAB3, and FSHR genes with reproductive traits in different sheep breeds

“…Studies have shown that the SLK gene is commonly expressed in adult tissues, cell lines, and developing mouse embryos (Sabourin and Rudnicki, 1999;Zhang et al, 2002). Song et al (2023) found that SLK is highly expressed in mouse oocyte meiosis with upregulated phosphorylation modifications. SLK has also been shown to be required for cell cycle progression from G2 to mitosis (G2/M) by activating the polo-like kinase homolog (PLK1), an essential kinase that regulates cell cycle trafficking, and cell cycle proteindependent kinases, and that SLK depletion results in the inability to downregulate cell cycle protein A and early G2 arrest (Ellinger-Ziegelbauer et al, 2000;O'Reilly et al, 2005).…”

KAT8 functions in redox homeostasis and mitochondrial dynamics during mouse oocyte meiosis progression

“…Mammalian oocytes of high quality are of paramount importance for fertilization, with positive consequences for embryo development 1 . During mammalian meiosis, oocytes are arrested in prophase I, which is also called the germinal vesicle (GV) stage.…”