Molecular cloning, characterisation and functional analysis of the duck Forkhead box O3 (FOXO3) gene

Mechanism and Functions of Identified miRNAs in Poultry Skeletal Muscle Development – A Review

Development of the skeletal muscle goes through several complex processes regulated by numerous genetic factors. Although much efforts have been made to understand the mechanisms involved in increased muscle yield, little work is done about the miRNAs and candidate genes that are involved in the skeletal muscle development in poultry. Comprehensive research of candidate genes and single nucleotide related to poultry muscle growth is yet to be experimentally unraveled. However, over a few periods, studies in miRNA have disclosed that they actively participate in muscle formation, differentiation, and determination in poultry. Specifically, miR-1, miR-133, and miR-206 influence tissue development, and they are highly expressed in the skeletal muscles. Candidate genes such as CEBPB, MUSTN1, MSTN, IGF1, FOXO3, mTOR, and NFKB1, have also been identified to express in the poultry skeletal muscles development. However, further researches, analysis, and comprehensive studies should be made on the various miRNAs and gene regulatory factors that influence the skeletal muscle development in poultry. The objective of this review is to summarize recent knowledge in miRNAs and their mode of action as well as transcription and candidate genes identified to regulate poultry skeletal muscle development.

Cellular function of chicken FOXO3 and its associations with chicken growth

FOXO3 belongs to the Forkhead O transcription factor family and it is an important gene in multiple biological processes, such as cell cycle control, cell proliferation, cell apoptosis, human longevity, and oxidative stress. Previous studies have shown that FOXO3 is associated with skeletal muscle growth and adipose development in mammals. However, the sequence of chicken FOXO3 is still incomplete and the cellular functions of FOXO3 in chickens are poorly understood. Thus, we obtained the full-length sequence of chicken FOXO3 by 5' rapid amplification of cDNA ends (5' RACE) and the phylogenetic tree showed that the chicken FOXO3 sequence was homologous with those in other species. Flow cytometry analysis and 5-ethynyl-2'-deoxyuridine assays showed that FOXO3 repressed cellular proliferation and induced apoptosis in a chicken hepatocellular carcinoma cell line (LMH). Mutations were screened in the second exon of FOXO3 and 13 synonymous single nucleotide polymorphisms were found in the test population. Further analysis showed that rs317670452 and rs15379317 were associated with many growth and carcass traits, such as the body weight at different ages and breast muscle weight. Our results indicate that chicken FOXO3 has similar cellular functions to those found in mammals and it is significantly associated with chicken growth.