A constitutively expressed serum amyloid A protein gene (SAA4) is closely linked to, and shares structural similarities with, an acute-phase serum amyloid A protein gene (SAA2).
The acute-phase reactant serum amyloid A (SAA) is a polymorphic apolipoprotein encoded by a family of highly homologous and closely linked genes: SAA1, SAA2, and SAA3. We have isolated a human genomic cosmid clone containing the gene encoding a fourth, constitutively expressed member of the human SAA superfamily, C-SAA, together with an SAA2*2 (SAA2 beta) gene. The gene encoding C-SAA shares the same 5' to 3' orientation as SAA2*2 and has the characteristic four-exon structure of the other members of the SAA superfamily. The exons of the gene encoding C-SAA share only limited sequence identity with those of SAA1, SAA2, and SAA3; they specify an mRNA, represented by the CS-1 cDNA reported previously by us, which is expressed at low levels (relative to the acute-phase SAAs) in normal and acute-phase liver. The gene encoding C-SAA is located 9 kb downstream of SAA2*2 and therefore occupies the locus that has been identified as containing the SAA4 gene.
Steel
D M
DM
Department of Genetics, Trinity College, University of Dublin, Ireland.
Sellar
G C
GC
Uhlar
C M
CM
Simon
S
S
DeBeer
F C
FC
Whitehead
A S
AS
D000209:Acute-Phase Proteins / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D005091:Exons; D005796:Genes; D008040:Genetic Linkage; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D012689:Sequence Homology, Nucleic Acid; D000685:Serum Amyloid A Protein / Q000235:genetics*
D000209:Acute-Phase Proteins; D000685:Serum Amyloid A Protein