Dog serum amyloid A protein. Identification of multiple isoforms defined by cDNA and protein analyses

• Published in: The Journal of biological chemistry Vol. 266; no. 6; pp. 3505 - 3510
• Main Authors: Sellar, G C, DeBeer, M C, Lelias, J M, Snyder, P W, Glickman, L T, Felsburg, P J, Whitehead, A S
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 25-02-1991; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; amyloid A; Analytical, structural and metabolic biochemistry; Animals; Base Sequence; Biological and medical sciences; DNA - genetics; Dogs; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; genes; Isoelectric Focusing; Lipoproteins, HDL - genetics; liver; Miscellaneous; Molecular Sequence Data; Proteins; Serum Amyloid A Protein - genetics; Molecular form; Nucleotide sequence; Gel electrophoresis; Pathogenesis; Liver; Inflammation; Proteins; Vertebrata; Serum amyloid protein SAA; Mammalia; Isoelectrical focusing; Polyadenylation; Serum; Molecular cloning; Lipoprotein HDL; Aminoacid sequence
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)67824-5

Five distinct serum amyloid A (SAA) cDNA clones have been isolated from a library constructed using hepatic mRNA isolated from an individual beagle dog with canine pain syndrome. This implies the existence of at least three SAA genes in the dog genome. One clone predicts a truncated “amyloid A-like” SAA molecule and offers a possible alternative mechanism for the pathogenesis of secondary amyloidosis. Relative to the human and mouse SAA proteins, an additional peptide of eight amino acids is specified by each of the dog cDNA clones. The existence of this peptide in all acute phase dog SAA proteins was confirmed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate of acute phase high density lipoprotein and provides supporting evidence for gene conversion as a mechanism for maintaining the homogeneity of the SAA gene family within a species. Analysis of hepatic RNA following induction of an acute phase response shows a dramatic increase in SAA mRNA concentration; the SAA transcripts show a transient increase in size early in inflammation due to an increase in polyadenylation.