Abstract
Four serum amyloid A protein (SAA) genes and two gene products, apo-SAA1 and apo-SAA2 were identified in BALB/c mice (type A). SJL/J mice (type B) are thought to be defective in apo-SAA2 expression. A unique variant of mouse apo-SAA was identified in SJL/J mice by isoelectric-focusing analysis of high-density lipoprotein from endotoxin-treated mice. Complete amino-acid-sequence analysis of this quantitatively major form of SJL/J apo-SAA (pI 5.9) showed it to be identical with the apo-SAA2 isoform from BALB/c mice, except for the substitution of aspartic acid for alanine at position 101. Isoform-specific analysis of mRNA from liver of BALB/c and SJL/J mice and their F1 hybrid progeny (CSJLF1/J) mice revealed further differences in the 3' untranslated regions of the genes, not only encoding apo-SAA2 and apo-SAA pI 5.9, but also apo-SAA1. The SAA genes of SJL/J mice thus differ from BALB/c in exon 4. Additional minor isoforms corresponding to apo-SAA2 (pI 6.3) in SJL/J mice and apo-SAA (pI 5.9) in BALB/c mice were identified. We propose that, when analysing a multigene family such as SAA, thorough analysis at the protein level should complement molecular-biological approaches where the use of a too-limited repertoire of probes can obscure complexities.
Original language | English |
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Pages (from-to) | 673-678 |
Number of pages | 6 |
Journal | Biochemical Journal |
Volume | 283 |
Issue number | 3 |
DOIs | |
State | Published - 1992 |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology