title: Cloning, comparative characterization of porcine SCAP gene, and identification of its two splice variants.
abstract: Sterol responsive element binding protein (SREBP) cleavage-activating protein (SCAP) is the key regulator of activation of SREBPs, which stimulate most enzymes in cholesterol and lipid synthesis. In order to investigate the molecular basis of lipid metabolism in the pig, a unique model for fat deposition, we isolated and characterized the porcine SCAP. The 4,096-bp full-length porcine SCAP cDNA contains an open reading frame of 3,840 bp. The predicted SCAP protein consists of 1,280 amino acids of 55-92% identity with its vertebrate counterparts. The porcine SCAP gene consists of at least 19 exons and 18 introns, which span over 13 kb of the genome. The porcine SCAP gene was mapped to chromosome 13q21-22 using a porcine-rodent somatic cell hybrid panel. Comparison of SCAP genomic structures from various species revealed intron losses in porcine, Tetraodon and fugu SCAP, and intron gains in cow and chicken SCAP. Moreover, we isolated two novel splicing SCAP variants with 193-bp (variant 2) in-frame deletion from testis and a variant with 291-bp (variant 3) in-frame deletion from liver and muscle, which may affect the function of the porcine SCAP. In conclusion, the intron gains and losses appear to have contributed to the shape of the modern SCAP family. The splice variants detected, first to be reported in any species, may be involved in the particulars of the fat metabolism in the pig. Our data lay foundation for further study of SCAP function in this species.
authors.affiliation: Lab of Biochemistry, College of Life Science and Technology, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
authors.forename: Huan
authors.initials: H
authors.lastname: Qiu
authors.forename: Tao
authors.initials: T
authors.lastname: Xia
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Chen
authors.forename: Xuelian
authors.initials: X
authors.lastname: Zhao
authors.forename: Li
authors.initials: L
authors.lastname: Gan
authors.forename: Shengqiu
authors.initials: S
authors.lastname: Feng
authors.forename: Ting
authors.initials: T
authors.lastname: Lei
authors.forename: Zaiqing
authors.initials: Z
authors.lastname: Yang
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D002784:Cholesterol / Q000096:biosynthesis / Q000235:genetics; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics; D003001:Cloning, Molecular; D005091:Exons / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins; D007438:Introns / Q000235:genetics; D050356:Lipid Metabolism / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051779:Sterol Regulatory Element Binding Proteins / Q000235:genetics / Q000378:metabolism; D013552:Swine / Q000235:genetics* / Q000378:metabolism
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C102196:SREBP cleavage-activating protein; D051779:Sterol Regulatory Element Binding Proteins; D002784:Cholesterol