Increasing evidence suggests that miRNA binding-site polymorphism in the 3'-untranslated region (3'UTR) of a target gene could affect that gene's expression, and can be associated with a variety of complex traits. In this study, we find that miR-18a and cell division cycle 42 (CDC42) mRNA, whose expression was inversely correlated, are differentially expressed in porcine placentas during critical stages of placental development. rs55618224 (T>C), a SNP in the 3'UTR region of CDC42 that is perfectly complementary to the miR-18a seed could influence miR-18a-related regulation of CDC42 gene by altering their binding affinity. In addition, CDC42 mRNA was found to have higher expression level in the homozygous TT placentas as compared to those homozygous CC placentas in pigs. Furthermore, we identified a significant association between rs55618224 and total number born per litter. These results suggest the miR-18a binding-site polymorphism in CDC42 3'UTR may impact litter size by regulation of CDC42 gene in porcine placentas.

中文翻译：

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CDC42 3'UTR中的miR-18a结合位点多态性影响胎盘中CDC42 mRNA的表达，并与猪的产仔数有关。

越来越多的证据表明，靶基因3'-非翻译区（3'UTR）中的miRNA结合位点多态性可能影响该基因的表达，并可能与多种复杂性状相关。在这项研究中，我们发现miR-18a和细胞分裂周期42（CDC42）mRNA表达呈负相关，在胎盘发育的关键阶段在猪胎盘中差异表达。rs55618224（T> C）是CDC42的3'UTR区中与miR-18a种子完全互补的SNP，可通过改变其结合亲和力来影响miR-18a相关的CDC42基因调控。另外，发现与猪中纯合CC胎盘相比，CDC42 mRNA在纯合TT胎盘中具有更高的表达水平。此外，我们发现rs55618224与每窝出生总数之间存在显着关联。这些结果表明，CDC42 3'UTR中的miR-18a结合位点多态性可能通过调节猪胎盘中CDC42基因而影响产仔数。