title: Genomic structural analysis of porcine fatty acid desaturase cluster on chromosome 2.
abstract: Fatty acid composition is an economically important trait in meat-producing livestock. To gain insight into the molecular genetics of fatty acid desaturase (FADS) genes in pigs, we investigated the genomic structure of the porcine FADS gene family on chromosome 2. We also examined the tissue distribution of FADS gene expression. The genomic structure of FADS family in mammals consists of three isoforms FADS1, FADS2 and FADS3. However, porcine FADS cluster in the latest pig genome assembly (Sscrofa 10.2) containing some gaps is distinct from that in other mammals. We therefore sought to determine the genomic structure, including the FADS cluster in a 200-kbp range by sequencing gap regions. The structure we obtained was similar to that in other mammals. We then investigated the porcine FADS1 transcription start site and identified a novel isoform named FADS1b. Phylogenetic analysis revealed that the three members of the FADS cluster were orthologous among mammals, whereas the various FADS1 isoforms identified in pigs, mice and cattle might be attributable to species-specific transcriptional regulation with alternative promoters. Porcine FADS1b and FADS3 isoforms were predominantly expressed in the inner layer of the subcutaneous adipose tissue. Additional analyses will reveal the effects of these functionally unknown isoforms on fatty acid composition in pig fat tissues.
authors.affiliation: Animal Genome Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Taniguchi
authors.forename: Aisaku
authors.initials: A
authors.lastname: Arakawa
authors.forename: Michiyo
authors.initials: M
authors.lastname: Motoyama
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Nakajima
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nii
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mikawa
mesh_terms: D000818:Animals; D002417:Cattle; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics*; D000090943:Delta-5 Fatty Acid Desaturase; D044943:Fatty Acid Desaturases / Q000235:genetics*; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D063427:Food Quality; D016678:Genome; D023281:Genomics; D006801:Humans; D008460:Meat; D051379:Mice; D008969:Molecular Sequence Data; D020033:Protein Isoforms; D013045:Species Specificity; D050151:Subcutaneous Fat / Q000201:enzymology; D013552:Swine / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D000090943:Delta-5 Fatty Acid Desaturase; D005227:Fatty Acids; D020033:Protein Isoforms; D044943:Fatty Acid Desaturases; C000716847:FADS1 protein, human
keywords: adipocyte; alternative transcription; fatty acid desaturase; genomic structure; porcine