| MicroRNA(miRNA) is one of noncoding RNAs which is mainly involved in the regulation of growth development and reproduction of animal by the way of target-specific post-transcriptional repression. The expression profile of miRNA is depended on development stage and tissue specificity pattern. Xiang pig is specific for its dwarf in body and early sexual maturity with low litter size. However, it is still unclear for the mechanism of low fecundity in Xiang pig.Based on the small RNA library of testis at four months of age, the expressed miRNAs were detected by the HiSeq sequencing platform. With the help of many bioinformatics softwares, the expression profile of testis was identified from Xiang pig at different months of age. The miRNA expressed differently in testis was further analyzed and the target genes were deduced. Six miRNA molecular were chosen to determine the expression level in different tissues and different ages. The results were as follows.1. The sperms were observed at the convoluted tubules of testis in Xiang pig.2. The expression profiles were described in testis of Xiang pig at 2, 3, 7, 18 months of age.About 6 million sequences with high quality were collected from every library of sample.3. A total of 254 known miRNAs and 180 candidate miRNAs were identified from the small RNA library in 2 months of age. It was 251 and 176 miRNAs from library of 3 months, 227 and120 miRNAs from library in 7 months, 215 and 100 miRNAs from library of 18 months,respectively. In addition, 6 miRNAs were confirmed to express in testis at four ages of Xiang pig by RT-qPCR method.4. 1165 miRNAs were expressed differently in the four libraries. 74 miRNAs in library of 2months were significantly lower than that of 3 months. Compared with the miRNA level in testis at 7 and 18 months of ages, the level of 219 and 224 miRNA was higher in testis at 2 months of age, respectively. The level of 268 miRNA and 272 mi RNA were higher in testis at 3 months than that at 7 or 18 months of ages. The expression amount of 21 miRNA in testis at 7 months of age was much higher than that in 18 months. The highest level of miRNA was found out from testis at2 months of age while the lowest one was at 18 months.5. A total of 1953 target genes were found out when ten miRNAs were chosen for analysis bymirecord software. Based on KEGG pathway results, these target genes might be involved in the regulation of development and generation of sperm in testis of Xiang pig.6. Six miRNA were detected from testis of Xiang pig from one month to seven months by real time qRT-PCR. The expression amount of Let-7a-5p and mi R-10 were increased first and then decreased, miR-202 level was decreased gradually, miR-200 b level was decreased first then increased, while the trend of the others, mi R-145-5p and miR-199a-3p, showed irregularly.In sum, the mi RNA expression profile was researched in testis at different ages of Xiang pig. It would be helpful for understanding for the molecular mechanism of testis development in Xiang pig breed. |
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