DNA sequence evidence for polymorphic forms of human serum amyloid A (SAA)

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Serum amyloid A (SAA) is an acute-phase reactant and precursor to amyloid A protein.
• SAA forms the major component of fibril deposits in reactive amyloidosis.
• The specific factors driving SAA conversion to amyloid A protein and fibril deposition remain unknown.

Purpose of the Study:

• To investigate the role of SAA primary structure in amyloid formation.
• To clone and determine the nucleotide sequence of human SAA-specific cDNAs.

Main Methods:

• Oligonucleotide probe selection of SAA-specific cDNAs.
• Differential screening using a PstI site to identify distinct SAA cDNA clones (pSAA21 and pSAA82).
• Complete nucleotide sequence determination of pSAA82 cDNA.

Main Results:

• Successfully cloned and sequenced human SAA-specific cDNAs.
• Identified two distinct full-length SAA cDNAs, pSAA21 and pSAA82, differing by a PstI site.
• Determined the complete nucleotide sequence of pSAA82 cDNA.

Conclusions:

• The nucleotide sequences of human SAA cDNAs have been elucidated.
• Multiple human SAA alleles may exist.
• Differential expression of SAA alleles could be crucial for amyloid formation.