title: Cloning and identification of porcine SMPX differentially expressed in F1 crossbreds and their parents.
abstract: In order to investigate porcine heterosis on the molecular basis, Large White (L), a European purebred, and Meishan (M), a Chinese indigenous purebred, were hybridized directly and reciprocally to produce F1 hybrids, Large WhitexMeishan (LM) and MeishanxLarge White (ML) pigs. Using mRNA differential display, we found an expression sequence tag (EST) differentially expressed in F1 hybrids and their parents, designated as EST55, which was homologous to human and murine skeletal muscle protein (SMPX), and the full-length cDNA of porcine SMPX was cloned by the rapid amplification of cDNA end (RACE) method. Translation of the mRNA transcript revealed an open reading frame (ORF) of 86 amino acid residues encoding a nuclear location signal peptide, two overlapping casein kinase II phosphorylation sites and one N-glycosylation site with theoretical molecular weight of 9.3 kDa. Alignment analysis revealed that the deduced protein sequence shared 94%, 83% and 78% homology with that of its human, mouse and rat counterparts, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that it was expressed predominantly in skeletal and heart muscles, whereas at a moderate level in backfat, spleen, stomach and uterus tissues. Two single nucleotide polymorphism (SNPs), located in 5'- and 3'-untranslated region (UTR), respectively,were identified by PCR and sequencing. Phylogenetic tree and the secondary structure prediction were also performed. The possible relationship between porcine SMPX and heterosis was discussed.
authors.affiliation: Agricultural Ministry Key Laboratory of Swine Breeding and Genetics, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Zhu-Qing
authors.initials: ZQ
authors.lastname: Ren
authors.forename: Yuan-Zhu
authors.initials: YZ
authors.lastname: Xiong
authors.forename: Chang-Yan
authors.initials: CY
authors.lastname: Deng
authors.forename: Ming-Gang
authors.initials: MG
authors.lastname: Lei
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001947:Breeding; D003433:Crosses, Genetic; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D019913:Nuclear Localization Signals / Q000235:genetics / Q000378:metabolism; D009928:Organ Specificity; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D034421:Sus scrofa / Q000235:genetics* / Q000378:metabolism
chemical_list: D009124:Muscle Proteins; D019913:Nuclear Localization Signals; D012333:RNA, Messenger