Three different serum amyloid a cDNA and protein sequences in one individual: evidence for at least two genes
Serum amyloid A (SAA) is an acute phase reactant and precursor to amyloid A protein, the major constituent of reactive amyloid fibrils. Based on the finding that the primary structure of SAA is polymorphic, they are pursuing studies to determine if particular SAA gene sequences are related to the development of amyloidosis. They have previously reported the structure of two human SAA cDNA clones and have localized all complementary gene sequences to the short arm of chromosome 11. The authors now present a third distinct SAA cDNA clone isolated from the same library. The three cDNAs show a high degree of sequence homology within the coding region (> 90%), yet encode a number of amino acid differences, and therefore indicate the presence of at least two SAA genes. All three DNA sequences were expressed in the individual from whom the cDNA library was derived as shown by the isolation and amino acid sequence determination of the corresponding SAA proteins. In addition to the cDNAs, a 3 kb SAA genomic fragment has been cloned and used to investigate gene number. A comparison of the fragments of total DNA which hybridize to the genomic clone versus those which hybridize to the cDNA clones strongly points to the existence of two very homologous SAA genes, one of which has at least two different alleles. Southern analyses of Hind III-digested total DNA suggest the possible presence of a third, more divergent human SAA gene.
- Research Organization:
- Indiana Univ. School of Medicine, Indianapolis
- OSTI ID:
- 6286691
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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