Reddy Alavala Matta, Zheng Yun, Jagadeeswaran Guru, Macmil Simone L, Graham Wiley B, Roe Bruce A, Desilva Udaya, Zhang Weixiong, Sunkar Ramanjulu
Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA.
BMC Genomics. 2009 Feb 5;10:65. doi: 10.1186/1471-2164-10-65.
MicroRNAs (miRNAs) are small ~22-nt regulatory RNAs that can silence target genes, by blocking their protein production or degrading the mRNAs. Pig is an important animal in the agriculture industry because of its utility in the meat production. Besides, pig has tremendous biomedical importance as a model organism because of its closer proximity to humans than the mouse model. Several hundreds of miRNAs have been identified from mammals, humans, mice and rats, but little is known about the miRNA component in the pig genome. Here, we adopted an experimental approach to identify conserved and unique miRNAs and characterize their expression patterns in diverse tissues of pig.
By sequencing a small RNA library generated using pooled RNA from the pig heart, liver and thymus; we identified a total of 120 conserved miRNA homologs in pig. Expression analysis of conserved miRNAs in 14 different tissue types revealed heart-specific expression of miR-499 and miR-208 and liver-specific expression of miR-122. Additionally, miR-1 and miR-133 in the heart, miR-181a and miR-142-3p in the thymus, miR-194 in the liver, and miR-143 in the stomach showed the highest levels of expression. miR-22, miR-26b, miR-29c and miR-30c showed ubiquitous expression in diverse tissues. The expression patterns of pig-specific miRNAs also varied among the tissues examined.
Identification of 120 miRNAs and determination of the spatial expression patterns of a sub-set of these in the pig is a valuable resource for molecular biologists, breeders, and biomedical investigators interested in post-transcriptional gene regulation in pig and in related mammals, including humans.
微小RNA（miRNA）是一类约22个核苷酸的小调节RNA，可通过阻断靶基因的蛋白质生成或降解mRNA来使其沉默。猪是农业产业中的重要动物，因其在肉类生产中的用途。此外，猪作为模式生物具有巨大的生物医学重要性，因为它比小鼠模型更接近人类。已经从哺乳动物、人类、小鼠和大鼠中鉴定出数百种miRNA，但对猪基因组中的miRNA组成了解甚少。在此，我们采用实验方法来鉴定保守和独特的miRNA，并表征它们在猪不同组织中的表达模式。
通过对使用来自猪心脏、肝脏和胸腺的混合RNA构建的小RNA文库进行测序，我们在猪中总共鉴定出120个保守的miRNA同源物。对14种不同组织类型中保守miRNA的表达分析揭示了miR-499和miR-208在心脏中的特异性表达以及miR-122在肝脏中的特异性表达。此外，心脏中的miR-1和miR-133、胸腺中的miR-181a和miR-142-3p、肝脏中的miR-194以及胃中的miR-143表达水平最高。miR-22、miR-26b、miR-29c和miR-30c在不同组织中普遍表达。猪特异性miRNA的表达模式在检测的组织中也有所不同。
鉴定出120种miRNA并确定其中一部分在猪中的空间表达模式，对于对猪及包括人类在内的相关哺乳动物转录后基因调控感兴趣的分子生物学家、育种者和生物医学研究人员来说是一项宝贵的资源。
