Abstract
miR-155 has multiple functions in many physiological and pathological processes. However, little is known about the expression characteristics of avian miR-155. In the present study, partial pri-miR-155 sequences were cloned from AA+ broiler, Sanhuang broiler and Hy-Line Brown layer, respectively. Stem–loop qRT-PCR was performed to detect the miR-155-5p spatiotemporal expression profiles of each chicken breed, and the target genes of miR-155-5p were predicted in Gene Oncology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The results showed that the partial pri-miR-155 sequences of different breeds of chicken were high conserved. The expression patterns of miR-155-5p between broiler and layer were basically similar, and miR-155-5p was expressed highly in immune related tissues (spleen, thymus and bursa). In the same old chicken (14 days old), miR-155-5p expression activity of fat tissue all had higher level in the three chicken breeds, but the expression activities in skeletal muscle of broilers were significantly lower than that of layer (P<0.05). In different development stages of Hy-Line Brown layer, miR-155-5p expression activities in skeletal muscle of 14-day-old and 10-month-old layers were significantly lower than that of 24-month-old layer (P<0.05). Fat related target genes (ACOX1, ACOT7, FADS1, SCD and HSD17B12) and skeletal muscle related target genes (CCNT2, DMD, CFL2, MAPK14, FLNB, ZBTB18 and CDK5) of miR-155-5p were predicted, respectively. The results indicate that miR-155-5p may be an important factor inhibiting the fat deposition and skeletal muscle development in chicken.
Highlights
MicroRNAs are a class of endogenous non-coding regulatory RNAs, which are 18–23 nucleotides in length and negatively regulate gene expression at the posttranscriptional levels. miRNAs play critical roles in many biological processes, including cell proliferation, differentiation, development and functions [1,2,3,4]
Homologous comparison of sequencing results revealed that the three partial pri-miR-155 sequences of each chicken breed shared the identical sequences with equal length (263 bp), and no deletion or insertion event was detected (Figure 1)
All miR-155-5p had low expression activities in skeletal muscle, we found that the expression activities of miR-155-5p in 14-day-old broilers (AA+ broiler and Sanhuang broiler) were significantly lower than that of 14-day-old Hy-Line Brown layer
Summary
MicroRNAs (miRNAs) are a class of endogenous non-coding regulatory RNAs, which are 18–23 nucleotides in length and negatively regulate gene expression at the posttranscriptional levels. miRNAs play critical roles in many biological processes, including cell proliferation, differentiation, development and functions [1,2,3,4]. Numerous studies have shown that miR-155 plays important roles in the immune system and can affect the activation of B, T cell and lymphocytes through controlling manifold regulatory roles [5,6,7,8,9]. MiR-155 can repress the expression of MEF2A (a member of the myogenic enhancer factor 2 family of transcription factors) and osteoglycin (Ogn, an important component of the skeletal muscle secretome), and inhibit proliferation and differentiation of myoblast cells [10,11]. MiR-155 regulates the expression of Olfactomedin-like 3 (OLFML3), which may affect prenatal skeletal muscle development in pig [12]. MiR-155 can inhibit adipogenesis by directly targeting CCAAT/enhancer-binding protein β (C/EBPβ), cAMP-response element binding protein (CREB) and peroxisome proliferator-activated receptor gamma (PPARγ) [13,14,15]. MiR-155 and C/EBPβ co-regulate the development of brown and beige fat cells via a bistable circuit [16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
