2020  1,374
2019  1,023
2018  0,932
2017  0,977
2016  0,799
2015  0,662
2014  0,740
2013  0,739
2012  0,637
2011  0,658
2010  0,654
2009  0,570
2008  0,849
2007  0,805
2006  0,330
2005  0,435
2004  0,623
2003  0,567
2002  0,641
2001  0,490
2000  0,477
1999  0,762
1998  0,785
1997  0,507
1996  0,518
1995  0,502
Vol 45(2011) N 2 p. 197-203;
Yong Huang1,2, Xing Jia Shen1,2*, Quan Zou3, Jin Shan Huang1,2, Shun Ming Tang1,2

Genomic analysis of silkworm microRNA promoters and clusters

1The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, 212018, China
2Jiang Su University of Science and Technology, Zhenjiang, 212018, China
3School of Information Science and Technology of Xiamen University, Xiamen, 361005, China

Received - 2010-02-08; Accepted - 2010-04-21

MicroRNAs (miRNAs) are endogenous single-stranded RNAs of 18~22 nt in length, which can regulate the complementary mRNAs at the post-transcriptional level by cleavage or repression of translation of the target mRNAs. Studies have shown that the majority of animal miRNAs are transcribed from independent transcription units, and some are transcribed together with their host genes. However, the nature of the primary transcript of intergenic miRNAs remains unknown. Silkworm (Bombyx mori) miRNAs are representative of those of the Lepidoptera insects and many of them are conserved in Caenorhabditis elegans and other animal species. To date, little is known about the transcriptional regulation of silkworm miRNA genes. We performed the genomic analysis on the silkworm miRNA transcripts around the promoter region including the transcription start site (TSS) and the TATA-box, and on the organization of the miRNA cluster. In 73 pre-miRNAs from the silkworm 131 promoters were detected via a bioinformatics approach. Among them the portion of non-conserved promoters is greater than that of the conserved ones. The genomic organization of pre-miRNAs of the silkworm was globally analyzed and it was determined that 11 of them were organized into five clusters. Sequence alignment showed that paralogs existed for some of the miRNAs in the cluster. These results may increase the understanding of the specific sequences upstream of the pre-miRNAs and of the functional implications of miRNA clusters in the silkworm.

microRNA, Bombyx mori, promoter, miRNA cluster