Cloning and expression of hepatic synaptotagmin 1 in mouse.
Mouse hepatic synaptotagmin 1 (SYT1) cDNA was cloned, characterized and compared to the brain one. The hepatic transcript was 1807 bp in length, smaller than the brain, and only encoded by 9 of 11 gene exons. In this regard, 5'-and 3'-untranslated regions were 66 and 476 bp, respectively; the open reading frame of 1266 bp codified for a protein of 421 amino acids, identical to the brain, with a predicted molecular mass of 47.4 kDa and highly conserved across different species. Immunoblotting of protein showed two isoforms of higher molecular masses than the theoretical prediction based on amino acid sequence suggesting posttranslational modifications. Subcellular distribution of protein isoforms corresponded to plasma membrane, lysosomes and microsomes and was identical between the brain and liver. Nonetheless, the highest molecular weight isoform was smaller in the liver, irrespective of subcellular location. Quantitative mRNA tissue distribution showed that it was widely expressed and that the highest values corresponded to the brain, followed by the liver, spleen, abdominal fat, intestine and skeletal muscle. These findings indicate tissue-specific splicing of the gene and posttranslational modification and the variation in expression in the different tissues might suggest a different requirement of SYT1 for the specific function in each organ.
Departamento Bioquímica y Biología Molecular y Celular, Facultad de Veterinaria, Instituto de Investigación Sanitaria de Aragón (IIS), Universidad de Zaragoza, Spain.
Sara
S
Sancho-Knapik
Departamento de Toxicología, Facultad de Veterinaria, Universidad de Zaragoza, Spain.
Natalia
N
Guillén
Departamento Bioquímica y Biología Molecular y Celular, Facultad de Veterinaria, Instituto de Investigación Sanitaria de Aragón (IIS), Universidad de Zaragoza, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Spain. Electronic address: Josada@unizar.es.
Jesús
J
Osada
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D015870:Gene Expression; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D011499:Protein Processing, Post-Translational; D017386:Sequence Homology, Amino Acid; D050863:Synaptotagmin I / Q000096:biosynthesis / Q000235:genetics*
D050863:Synaptotagmin I; C494311:Syt1 protein, mouse
Hepatic expression; Mouse; Synaptotagmin 1; Syt1