Molecular cloning and characterization of the chicken cationic amino acid transporter-2 gene.
The system y(+) cationic amino acid transporters (CATs) play an important role in the regulation of lysine and arginine utilization. We have characterized the genomic organization and tissue transcription of the chicken CAT-2 (cCAT-2) isoforms from pectoralis muscle. The primary cCAT-2 transcript is alternatively spliced within the same position of the mRNA to produce cCAT-2A and cCAT-2B isoforms that share high nucleotide homology with their mammalian counterparts. We also identified a novel third CAT-2 isoform, cCAT-2C. This isoform contains a premature termination codon and studies in the chicken LMH cell line show that cCAT-2C mRNA is degraded by the nonsense-mediated mRNA decay pathway. All three cCAT-2 isoforms are transcribed in liver, pectoralis, gastrocnemius and heart. Chicken cCAT-2A was the predominant cCAT-2 isoform in liver, pectoralis and gastrocnemius. Analysis of the 5'-untranslated region of cCAT-2 identified multiple cCAT-2 promoters. Chicken CAT-2 promoter usage was tissue dependent and was not responsible for cCAT-2 isoform production. Analysis of genomic sequence upstream cCAT-2 promoter regions revealed binding sites for transcription factors involved in amino acid sensing, hormone signaling and immune function. These results provide insight into the role of the cCAT-2 gene and its regulation of lysine and arginine utilization in aves.
Humphrey
Brooke D
BD
Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA. bdhumphr@calpoly.edu
Kirsch
Sandra
S
Morris
Diane
D
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D027202:Cationic Amino Acid Transporter 2 / Q000235:genetics* / Q000378:metabolism; D002645:Chickens / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D008297:Male; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014018:Tissue Distribution; D014157:Transcription Factors / Q000378:metabolism; D020506:Untranslated Regions / Q000737:chemistry
D030161:Avian Proteins; D027202:Cationic Amino Acid Transporter 2; D018076:DNA, Complementary; D020033:Protein Isoforms; D012333:RNA, Messenger; D014157:Transcription Factors; D020506:Untranslated Regions