title: Identification of conserved microRNAs in Bombyx mori (silkworm) and regulation of fibroin L chain production by microRNAs in heterologous system.
abstract: MicroRNAs (miRNAs) are an extensive class of small non-coding RNAs with important roles in the regulation of gene expression. Little study has been performed on identifying miRNAs in Bombyx mori (silkworm). Here, 41 conserved miRNAs were identified by a computational homology search approach and some of them were selected and confirmed experimentally. Some characteristics such as position-specific nucleotide distribution, evolutionary conservation and clustered organization have been described. Through general method of miRNA target identification, we also find that at least 4 miRNAs (miR-33/-190/-276/-7) target fibroin L chain transcripts, suggesting that miRNAs might play an important role in the regulation of silk protein production. In order to validate this, 3'-UTR of fibroin L chain mRNA was cloned and several expression vectors were constructed. Assays of semi-RT-PCR, histochemical and biochemical assays after agroinfiltration indicated that miRNAs can repress reporter gene (GUS) expression with sequence complement. Clearly, agroinfiltration proved a highly efficient method to identify the function of miRNAs inhibiting their targets mRNA in heterologous system.
authors.affiliation: Institute of Biochemistry, College of Life Science, Zijingang Campus, Zhejiang University, Hangzhou, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Cao
authors.forename: Chuanzhou
authors.initials: C
authors.lastname: Tong
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Wu
authors.forename: Jianning
authors.initials: J
authors.lastname: Lv
authors.forename: Zhaolin
authors.initials: Z
authors.lastname: Yang
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Jin
mesh_terms: D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics*; D017124:Conserved Sequence; D005349:Fibroins / Q000235:genetics* / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism*; D007814:Larva; D035683:MicroRNAs / Q000235:genetics*; D010060:Ovulation; D011679:Pupa
chemical_list: D019476:Insect Proteins; C432480:L-chain, fibroin protein, insect; D035683:MicroRNAs; D005349:Fibroins