MicroRNA (miRNA)-1 and miRNA-133 are derived from the same bicistronic pairs with roles in skeletal muscle development. Many investigations have focused on the role of miRNA-1 and miRNA-133 in the regulation of skeletal muscle development in mammals and fish. However, the mechanisms of miRNA-1 and miRNA-133 underlying the differences in skeletal muscle development between different breeds are not well known.Our study found that the weights of body and breast at 42 days of age were greater in Cherry Valley ducks than in Putian ducks and the areas of breast muscle fibers increased with age; the areas of muscle fibers of Cherry Valley ducks were always greater than those of Putian ducks. Besides, quantitative reverse-transcriptase polymerase chain reaction analysis revealed that relatively high levels of miRNA-1 and miRNA-133 were detected in heart, breast, and leg muscles compared with the liver, spleen, lung, kidney, and the expression levels of miRNA-1 and miRNA-133 remained stable in the embryo stage, and in the growth period, the fluctuation in miRNA expression levels in Putian ducks was considerably higher than that in Cherry Valley ducks, especially from 7 to 28 days.However, in the late growth period, the expression of miRNA-1 and miRNA-133 of CherryValley duck was higher than that of Putian duck, which may indicate that miRNA-1 and miRNA-133 play a more important role during the growth period. To determine the function of miRNA-1 and miRNA-133 in skeletal muscle development, we found that the overexpression of miRNA-1, but not miRNA-133, promoted fusion of adjacent myoblasts.By contrast, a repressor of miRNA-1 promoted, whereas a miRNA-133 inhibitor inhibited, myoblast proliferation. Accordingly, the expression levels of myocyte enhancer factor 2D (MEF2D) and myogenic differentiation (MYOD) were significantly increased by an miRNA-1 mimic and the miRNA-133 inhibitor. In addition, we found that the expression levels of miRNA-1 significantly affected the expression of histone deacetylase 4 (HDAC4), and miRNA-133 affected serum response factor (SRF) and transforming growth factor β receptor 1 (TGFBR1) levels. However, dual-luciferase reporter assays revealed that only miRNA-1 directly inhibited pGL-HDAC4 luciferase reporter activity, whereas miRNA-133 did not affect pGL-SRF or pGL-TGFBR1 fluorescence activity. Taken together, these results suggest that miRNA-1 targets HDAC4 to promote the differentiation of duck myoblasts and miRNA-133 may affect SRF and TGFBR1 expression to promote proliferation, which indicates that miRNA-1 and miRNA-133 play different important roles in skeletal muscle development. K E Y W O R D S duck, microRNA-1, microRNA-133, proliferation and differentiation, skeletal muscle J Cell Physiol. 2019;234:3490-3499. wileyonlinelibrary.com/journal/jcp 3490 |

1. Endothelin receptor B subtype 2 (EDNRB2) is a paralog of EDNRB, which encodes a 7-transmembrane G-protein coupled receptor. Previous studies reported that EDNRB was essential for melanoblast migration in mammals and ducks. 2. Muscovy ducks have different plumage colour phenotypes. Variations in EDNRB2 coding sequences (CDSs) and mRNA expression levels were investigated in 4 different Muscovy duck plumage colour phenotypes, including black, black mutant, silver and white head. 3. The EDNRB2 gene from Muscovy duck was cloned; it had a length of 6435 bp and encoded 437 amino acids. The coding region was screened and potential single nucleotide polymorphisms were identified. Eight mutations were obtained, including one missense variant (c.64C > T) and 7 synonymous substitutions. The substitutions were associated with plumage colour phenotypes. 4. The EDNRB2 mRNA expression levels were compared between feather pulp from black birds and black mutant birds. The results indicated that EDNRB2 transcripts in feather pulp were significantly higher in black feathers than in white feathers. 5. The results determined the variation of EDNRB2 CDS and mRNA expression in Muscovy ducks of various plumage colours.

1. The low reproductive performance of geese has seriously hampered the development of the industry. Reproductive performance, particularly the egg laying rate mainly depends on the development of the follicle. Previous studies have shown that follicle-stimulating hormone (FSH) plays an important role in the process of follicular development, but the exact underlying mechanism remains unclear. 2. This study showed that FSH stimulated granulosa cell proliferation in a dose-dependent manner. The effect of FSH treatment on granulosa cell proliferation was greatest at a dose of 100 mIU/ml FSH for 24 h. 3. Secondly, the effect of different concentrations of FSH on goose granulosa cell proliferation was investigated, and de novo transcriptome assembly and gene expression analysis performed using short-read sequencing technology (Illumina). High-throughput sequencing results yielded 62.61 M reads and 7.8 G base pairs from granulosa cells treated with 100 mIU/ml FSH. These reads were assembled into 65,757 unigenes (mean length: 705 bp) with an N50 of 903 bp. A total of 110 upregulated and 510 downregulated differentially expressed genes (DEGs) were identified by RNA-seq. 4. Functional analysis by gene ontology (GO) and KEGG pathway annotation indicated that hormone biosynthesis (GO:0042446), positive regulation of hormone secretion (GO:0046887), steroid biosynthesis, oxidative phosphorylation and carbon metabolism pathways were involved in FSH-mediated proliferation of goose granulosa cells. 5. After screening, a group of key responsive genes including superoxide dismutase 1, fatty acyl-CoA reductase 1, transforming growth factor-beta receptor-associated protein 1 and follistatin were tested by real-time reverse transcription PCR to confirm differential expression in granulosa cells stimulated by FSH. 6. FSH-stimulated goose granulosa cells and DEG profiling data provided comprehensive gene expression information at the transcriptional level that could promote better understanding of the molecular mechanisms underlying follicle development in response to FSH stimulation.

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1. The aim of this study was to identify the active control area of the duck retinoic acid-inducible gene I (duRIG-I) core promoter, to predict the binding sites of transcription factors and to provide a theoretical basis for the study of duRIG-I function and mechanism of regulation. 2. The promoter region of duRIG-I was obtained from Ensembl; the CpG island in the duRIG-I promoter was predicted online; and the methylation status of the duRIG-I promoter was detected by the bisulphite sequencing PCR method. 3. There was an obvious CpG island in the duRIG-I promoter, with a total of 44 CG dinucleotides. However, the level of methylation was hypomethylation (0.2%). 4. The core transcriptional regulatory region was identified, localised between -301 and ~+14 bp, where multiple transcription factor binding sites including IRF1, RXRβ, AP-2αA, RAP1, NF-1 and SP1 motifs were identified that significantly enhanced RIG-I promoter activity.