Granulosa cells (GCs) are somatic cells of ovary, the behaviors of GCs are important for ovarian function.  MicroRNAs (miRNAs) are a class of endogenous 18–24 nucleotide (nt) non-coding RNAs, some of which have been shown to be important regulators of GCs function.  miR-34c involved in the regulation of various biological processes and was identified to be a pro-apoptotic and anti-proliferative factor in many cell types.  However, the roles of miR-34c in GCs function remain unknown.  In this study, we used Annexin V-FITC and EdU assays to demonstrate that miR-34c exerted pro-apoptotic and anti-proliferative effects in porcine GCs.  Dual-luciferase reporter assays, quantitative real-time PCR (qRT-PCR) and Western blotting identified Forkhead box O3a (FoxO3a) as a direct target gene of miR-34c.  The overexpression of FoxO3a rescued the phenotypic change caused by miR-34c in porcine GCs.  In conclusion, miR-34c regulate the function of porcine GCs by targeting FoxO3a.

   MicroRNAs (miRNAs) are endogenous 18–24 nucleotide (nt) non-coding RNAs, some of which have been indicated to play key roles in granulosa cells (GCs) function. However, little is known about how the miRNA gene expression itself is regulated in the GCs. Our previous study showed that miR-34c, identified to be a pro-apoptotic and anti-proliferative factor in many cell types, exerted the same effects in porcine GCs. Here, the transcriptional regulation of miR-34c expression in GCs was further investigated. 5´ rapid amplification of cDNA ends (RACE) assay indicated that the pri-miR-34c transcription start site was located in 1 556 bp upstream of pre-miR-34c. With dual-luciferase reporter assay, we confirmed a 69 bp core promoter region (–1 799 bp/–1 730 bp) was indispensable for the transcription of miR-34c. Chromatin immunoprecipitation (ChIP) assay demonstrated that p53, p50, and p65 could bind to the transcription factor binding sites within the 69 bp core promoter region. In addition, deletion of transcripition factor binding sites resulted in obvious change of the miR-34c promoter activity. Finally, using overexpression and knockdown of p53, p50, and p65 strategies, we showed that p53 and p50 could positively regulated miR-34c expression, whereas p65 neletively regulated miR-34c expression in GCs. Our results provide new data about the transcription regulatory mechanism of miRNA genes in GCs.

    The objectives of this study were to estimate the genetic parameters and the breeding progress in a Landrace herd in China, and to predict the potential benefits by applying new breeding technology. Hereby, the performance records from a Landrace swine herd in China, composing over 33 000 pigs born between 2001 and 2013, were collected on six economically important traits, i.e., average daily gain between 30–100 kg (ADG), adjusted backfat thickness at 100 kg (BF), adjusted days to 30 kg (D30), adjusted days to 100 kg (D100), number born alive (NBA), and total number born (TNB). The genetic parameters were estimated by restricted maximum likelihood via DMU, and realized genetic trends were analyzed. Based on the real population structure and genetic parameters obtained from this herd, the potential genetic trends by applying genomic selection (GS) were predicted via a computer simulation study. Results showed that the heritability estimates in this Landrace herd were 0.55 (0.02), 0.42 (0.01), and 0.12 (0.01), for BF, D100, and TNB, respectively. Favorable genetic trends were obtained for D100, BF, and TNB due to direct selection, for ADG and NBA due to indirect selection. Long-term selection against D100 did not improve D30, though they are highly genetically correlated (0.64). Appling GS in such a swine herd, the genetic gain can be increased by 25%, or even larger for traits with low heritability or individuals without phenotypes before selection. It can be concluded that conventional breeding strategy was effective in the herd studied, while applying GS is promising and hence the road ahead in swine breeding.