Genetic linkage and expression analysis of SREBP and lipogenic genes in fat and lean chicken.
To identify the genes directly responsible, through DNA polymorphism, for the difference in fatness observed between a lean and a fat chicken line, we studied five genes (ACL, ACC, FAS, ME, SCD1) encoding key enzymes involved in liver fatty acid synthesis and secretion. Genetic linkage was tested between polymorphic sites in the genes and the fatness trait segregating in an F2 design obtained by inter-crossing the two fat and lean lines. Despite a confirmation of a higher mRNA level in the fat birds, no genetic linkage of the gene alleles with the phenotype could be found. As a test of the implication of upstream regulatory transcription factors, SREPB genes were also studied. The lack of genetic linkage of SREBP genes with fatness shows that these genes are not directly responsible through polymorphism for fatness variability in our model. Moreover, the similar SREBP mRNA levels observed between the two lines led us to exclude also transcriptional factors regulating the two SREBP genes as being directly responsible for fatness variability. However, the genes involved in post-translational modifications of SREBPs remain candidates to investigate. These results emphasised the interest to perform expression and genetic linkage studies jointly, to progress in identifying the genetic origin of variability of a quantitative trait.
Assaf
Sirine
S
UMR Génétique Animale, Institut National de la Recherche Agronomique-Ecole Nationale Supérieure Agronomique de Rennes, 65 rue de Saint-Brieuc, 35042 Rennes Cedex, France.
Lagarrigue
Sandrine
S
Daval
Stéphanie
S
Sansom
Manuella
M
Leclercq
Bernard
B
Michel
Joël
J
Pitel
Frédérique
F
Alizadeh
Mehdi
M
Vignal
Alain
A
Douaire
Madeleine
M
D000273:Adipose Tissue / Q000254:growth & development; D000818:Animals; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics*; D002645:Chickens; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis / Q000378:metabolism; D005786:Gene Expression Regulation; D008040:Genetic Linkage; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D008969:Molecular Sequence Data; D009765:Obesity / Q000235:genetics*; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D051780:Sterol Regulatory Element Binding Protein 1; D013851:Thinness / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D005227:Fatty Acids; D012333:RNA, Messenger; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors