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Abstract. Both microRNAs (miRNAs) and endogenous small interfering RNAs (endo-siRNAs) play key regulatory roles in gene expression. Some studies have demonstrated that the function of miRNA is suppressed in mouse oocytes, suggesting that endo-siRNA, not miRNA, is essential for female meiosis. This finding has yet to be confirmed in other species. In this study, by knockdown of DICER1, DROSHA and its cofactor DiGeorge syndrome critical region 8 (DGCR8) in porcine oocytes, we found that the proportion of oocytes with DICER1 deficiency that developed to meiosis II (MII) stage was significantly lower than oocytes with DROSHA and DGCR8 deficiency (39.23 versus 68.71 and 71.25% respectively; P , 0.05). Oocytes lacking DROSHA and DGCR8 formed a barrel-shaped metaphase I spindle, with chromosomes tightly aligned at the metaphase plate whereas most oocytes (87%) lacking DICER1 showed spindle abnormalities during oocyte in vitro maturation. Furthermore, DICER1 deficiency also resulted in oocyte apoptosis. These results indicate that endo-siRNAs are essential for oocyte maturation in pigs.

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Mesenchymal stem cells (MSCs) are pluripotent cells which can differentiate into several distinct lineages, such as chondrocytes, adipocytes and myofibers. It has been reported that the lineage-specific transcriptional factors including Runt related transcription factor 2 (RUNX2), Peroxisome proliferator-activator receptor gamma (PPARgamma) and Myogenic differentiation 1 (MyoD) may play key regulatory roles among the differentiation of MSCs. Recently, researches have confirmed that the Hippo pathway impacts the differentiation fates of MSCs through regulating the activity of line- age-specific transcription factors by the Hippo pathway effectors Tafazzin (TAZ) and/or Yes-associated protein (YAP). The interaction between TAZ and RUNX2 boosts the osteogenic processes and promotes MSCs differentiating into osteoblast lineage. However, PPARgamma binding to TAZ may inhibit the adipocytes differentiation, and thus overexpression of TAZ in mesenchymal stem cell-like cells increases the expression of myogenic genes and hastens myofiber formation through a MyoD-dependent manner. Moreover, other signaling pathways (such as BMP-2, TNF-alpha, Eph-Ephrin, etc.), small molecules (KR62980, TM-25659, etc.), and mechanistic stimuli can also affect the fate by regulating the activity of TAZ/YAP. In this review, we summarized the signaling pattern of Hippo pathway and the function mechanism of TAZ and/or YAP by enumerating their interaction to several lineage-specific transcriptional factors and relationship with other signal pathways during MSCs differentiation.

BackgroundDifferentiated cell nuclei can be reprogrammed to a pluripotent state in several ways, including incubation with oocyte extracts, transfer into enucleated oocytes, and induced pluripotent stem cell technology. Nuclear transfer-mediated reprogramming has been proven to be the most efficient method. Maternal factors stored in oocytes have critical roles on nuclear reprogramming and early embryo development, but remain elusive.ResultsIn this study, we showed most of porcine oocytes became nuclear matured at 33 h of IVM and the rate had no significant difference with oocytes at 42 h of IVM (p > 0.05). Moreover, the cleavage and blastocyst rates of SCNT and PA embryos derived from 42O were significantly higher than that of 33O (p < 0.05). But 33O could sustain IVF embryo development with higher cleavage and blastocyst rates comparing to 42O (p < 0.05). To clarify the development potential difference between 33O and 42O, 18 differentially expressed proteins were identified by proteomic analysis, and randomly selected proteins were confirmed by Western blot. Bioinformatic analysis of these proteins revealed that 33O highly synthesized proteins related to fertilization, and 42O was rich in nuclear reprogramming factors.ConclusionsThese results present a unique insight into maternal factors related to nuclear reprogramming and early embryo development.Electronic supplementary materialThe online version of this article (doi:10.1186/s12953-015-0074-5) contains supplementary material, which is available to authorized users.