title: Discovery, Characterization, and Functional Study of a Novel MEF2D CAG Repeat in Duck (Anas platyrhynchos).
abstract: Myocyte enhancer transcription factor 2D (MEF2D) is an important transcription factor for promoting the growth and development of muscle. CAG repeats have been found in the coding sequence (CDS) of avian MEF2D; however, their functions remain unknown and require further investigation. Here, we examined the characteristics and functional role of MEF2D CAG repeat in duck. The full-length CDS of duck MEF2D was cloned for the first time, and a novel CAG repeat was identified and located in exon 9. Sequence analysis indicated that the protein domains of duck MEF2D are highly conserved relative to other vertebrates, whereas MEF2D CAG repeats with variable repeat numbers are specific to avian species. Furthermore, sequencing has revealed polymorphisms in MEF2D CAG repeat at both DNA and mRNA levels. Four MEF2D CAG repeat genotypes and 10 MEF2D cDNA variants with different CAG repeat numbers were detected in two duck populations. A t-test showed that the expanded CAG repeat generated significantly longer transcription products (p < 0.05). Association analysis demonstrated positive correlations between the expansion of the CAG repeat and five muscle-related traits. By using protein structure prediction, we suggested that the polymorphisms of the CAG repeat affect protein structures within protein domains. Taken together, these findings reveal that duck MEF2D CAG repeat is a potential functional element with polymorphisms and may cause differences in MEF2D function between duck and other vertebrate species.
authors.affiliation: Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University , Chengdu, People's Republic of China .
authors.forename: Yushi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University , Chengdu, People's Republic of China .
authors.forename: Jiwen
authors.initials: J
authors.lastname: Wang
authors.affiliation: Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University , Chengdu, People's Republic of China .
authors.forename: Hehe
authors.initials: H
authors.lastname: Liu
authors.affiliation: Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University , Chengdu, People's Republic of China .
authors.forename: Rongping
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University , Chengdu, People's Republic of China .
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University , Chengdu, People's Republic of China .
authors.forename: Xiang
authors.initials: X
authors.lastname: Gan
authors.affiliation: Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University , Chengdu, People's Republic of China .
authors.forename: Huilan
authors.initials: H
authors.lastname: Huang
authors.affiliation: Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University , Chengdu, People's Republic of China .
authors.forename: Da
authors.initials: D
authors.lastname: Chen
authors.affiliation: Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University , Chengdu, People's Republic of China .
authors.forename: Liang
authors.initials: L
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004372:Ducks / Q000235:genetics / Q000254:growth & development; D005091:Exons; D015870:Gene Expression; D005838:Genotype; D064326:MEF2 Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D024510:Muscle Development / Q000235:genetics; D018482:Muscle, Skeletal / Q000254:growth & development / Q000378:metabolism*; D016366:Open Reading Frames; D011110:Polymorphism, Genetic; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D018911:Trinucleotide Repeats
chemical_list: D030161:Avian Proteins; D018076:DNA, Complementary; D064326:MEF2 Transcription Factors; D012333:RNA, Messenger