Evolution of Fish Let-7 MicroRNAs and Their Expression Correlated to Growth Development in Blunt Snout Bream

Abstract

Abstract:The lethal-7 (let-7) miRNA, known as one of the first founding miRNAs, is present in multiple copies in a genome and has diverse functions in animals. In this study, comparative genomic analysis of let-7 miRNAs members in fish species indicated that let-7 miRNA is a sequence conserved family in fish, while different species have the variable gene copy numbers. Among the ten members including let-7a/b/c/d/e/f/g/h/i/j, the let-7a precursor sequence was more similar to ancestral sequences, whereas other let-7 miRNA members were separate from the late differentiation of let-7a. The mostly predicted target genes of let-7 miRNAs are involved in biological process, especially developmental process and growth through Gene Ontology (GO) enrichment analysis. In order to identify the possible different functions of these ten miRNAs in fish growth development, their expression levels were quantified in adult males and females of Megalobrama amblycephala, as well as in 3-, 6-, and 12-months-old individuals with relatively slow-and fast-growth rates. These ten miRNAs had similar tissue expression patterns between males and females, with higher expression levels in the brain and pituitary than that in other tissues (p < 0.05). Among these miRNAs, the relative expression level of let-7a was the highest among almost all the tested tissues, followed by let-7b, let-7d and let-7c/e/f/g/h/i/j. As to the groups with different growth rates, the expression levels of let-7 miRNAs in pituitary and brain from the slow-growth group were always significantly higher than that in the fast-growth group (p < 0.05). These results suggest that let-7 miRNA members could play an important role in the regulation of growth development in M. amblycephala through negatively regulating expression of their target genes.

Inventory of European Sea Bass (Dicentrarchus labrax) sncRNAs Vital During Early Teleost Development

“…Five of the six identified miRNAs, namely miR-4792, let-7b-1, let-7b-2, miR-155-1, and miR-155-2, showed higher abundance in the M stage than in the FF stage ( Figure 5 ). Whereas let-7 is a well-studied miRNA belonging to the first founding miRNAs with possible roles in growth development (Kloosterman et al, 2004; Zhao et al, 2017), both miR-155 and miR-4792 have been examined less. Of the remaining miRNAs, miR-21 (ENSGACT00000028044.1) showed higher expression levels in the FF stage.…”

Induction of microRNA‑let‑7a inhibits lung adenocarcinoma cell growth by regulating cyclin�D1

“…Over the past two decades, numerous studies have indicated miRNA changes are associated with cancer biology, including cancer formation, development and metastasis ( 18 , 32 ). Let-7 miRNAs are underexpressed in the blood of patients with NSCLC ( 33 ) and expressed at lower levels in lung cancer ( 34 ). Similarly, the current results indicated that the expression of let-7a in lung adenocarcinoma tissues is reduced, suggesting that loss of let-7a may be a key factor in lung cancer development.…”

Genome-Wide Integrated Analysis Revealed Functions of lncRNA–miRNA–mRNA Interaction in Growth of Intermuscular Bones in Megalobrama amblycephala

“…So far, the miRNA-related studies had been reported in several fishes including zebrafish ( Danio rerio ), blunt snout bream ( Megalobrama amblycephala ), Botia superciliaris , and Pelteobagrus vachelli . These studies mainly pay attention to the regulatory role of miRNA in the growth (Zhao et al, 2017 ) and development of organs including the skeleton, gonad, skin, and liver (Gan et al, 2016 ; Zhang et al, 2016 ; Lan et al, 2019 ; Zhou et al, 2019 ). Nonetheless, there are few miRNA studies on fish IB development.…”