Core Binding Factor-β Knockdown Alters Ovarian Gene Expression and Function in the Mouse

Abstract

Core binding factor (CBF) is a heterodimeric transcription factor complex composed of a DNA-binding subunit, one of three runt-related transcription factor (RUNX) factors, and a non-DNA binding subunit, CBFβ. CBFβ is critical for DNA binding and stability of the CBF transcription factor complex. In the ovary, the LH surge increases the expression of Runx1 and Runx2 in periovulatory follicles, implicating a role for CBFs in the periovulatory process. The present study investigated the functional significance of CBFs (RUNX1/CBFβ and RUNX2/CBFβ) in the ovary by examining the ovarian phenotype of granulosa cell-specific CBFβ knockdown mice; CBFβ f/f * Cyp19 cre. The mutant female mice exhibited significant reductions in fertility, with smaller litter sizes, decreased progesterone during gestation, and fewer cumulus oocyte complexes collected after an induced superovulation. RNA sequencing and transcriptome assembly revealed altered expression of more than 200 mRNA transcripts in the granulosa cells of Cbfb knockdown mice after human chorionic gonadotropin stimulation in vitro. Among the affected transcripts are known regulators of ovulation and luteinization including Sfrp4, Sgk1, Lhcgr, Prlr, Wnt4, and Edn2 as well as many genes not yet characterized in the ovary. Cbfβ knockdown mice also exhibited decreased expression of key genes within the corpora lutea and morphological changes in the ovarian structure, including the presence of large antral follicles well into the luteal phase. Overall, these data suggest a role for CBFs as significant regulators of gene expression, ovulatory processes, and luteal development in the ovary.

Single-cell analysis of differences in transcriptomic profiles of oocytes and cumulus cells at GV, MI, MII stages from PCOS patients

“…PLCZ1 , which is significantly related to oocyte meiosis and the regulation of insulin secretion, can induce the activation of oocytes at the MII stage so that sperm and oocytes can fuse well2728. The expression of SFRP4 and ZMIZ1 , which are regulators of ovulation and luteinization, is lower in PCOS oocytes, indicating that the abnormal microenvironment of PCOS impacts luteinization negatively2930. ZSCAN4, a marker for the transition of RNA polymerase II-mediated transcription during GV oocyte maturation, is activated in GV oocyte31.…”

Allele-specific gene regulation by KDM6A

“…Our previous studies also implicated KDM6A in the regulation of reproduction related Hox genes Rhox6/9 (Berletch et al, 2013). Here we find that a number of genes with maternal allele-specific downregulation in KDM6A KO cells derived from the BC cross, including Dmrt1, Cbfb, and Stox2, are associated with reproductive processes (Fenstad et al, 2010;Matson et al, 2011;Tunster et al, 2016;Wilson et al, 2016). In addition, imprinted Xlr genes implicated in reproduction are downregulated in KDM6A KO cells, along with other maternally expressed imprinted genes, such as Meg3, a lncRNA gene that interacts with PRC2 components including JARID2 (da Rocha et al, 2014;Kaneko et al, 2014;Mondal et al, 2015;Yen et al, 2018).…”

Core Binding Factors are essential for ovulation, luteinization, and female fertility in mice

“…A list of selected up-regulated genes in gcRunx2;CbfbKO mice. * , genes which were previously identified to be differentially regulated in cultured granulosa cells isolated from Cbfb flox/flox ;Cyp19 cre mice compared to those from wild-type mice 9 . Fold changes were calculated by comparing the average values for mutant mouse samples vs. littermate control mouse samples (gcRunx2;CbfbKO/Wild-type).…”

“…Accumulating evidence using transgenic mouse models has identified such transcription factors including progesterone receptor (PGR), CCAAT/enhancer-binding protein alpha/beta (CEBPA/B), peroxisome proliferator-activated receptor γ (PPARG), the liver receptor homolog-1 (NR5A2), and nuclear receptor-interacting protein 1(NRIP1) [3][4][5][6][7] . Recent studies by our and other laboratories have shed light on a small family of transcription factors, the Core Binding Factors (CBFs), as critical mediators of the periovulatory process [8][9][10] .…”

“…CBFs play fundamental roles in tissue development, with each RUNX protein playing a distinct role(s) in the development of various tissues [11][12][13][14][15] . As a partner for all RUNX proteins, CBFB has shown to enhance the DNA binding activity and stability of RUNX proteins, thus is instrumental in the overall activity of CBFs 16-18 . In the ovary, the LH surge increases the expression of Runx1 and Runx2 in preovulatory follicles, while Cbfb is ubiquitously and constitutively expressed 9,[19][20][21] . Functional redundancy among RUNX proteins has been reported…”