Abstract
Mammary-associated serum amyloid A 3 (M-SAA3) was secreted at highly elevated levels in bovine, equine and ovine colostrum and found at lower levels in milk 4 days postparturition. N-terminal sequencing of the mature M-SAA3 protein from all the three species revealed a conserved four amino acid motif (TFLK) within the first eight residues. This motif has not been reported to be present in any of the hepatically-produced acute phase SAA (A-SAA) isoforms. Cloning of the bovine M-Saa3 cDNA from mammary gland epithelial cells revealed an open reading frame that encoded a precursor protein of 131 amino acids which included an 18 amino acid signal peptide. The predicted 113 residue mature M-SAA3 protein had a theoretical molecular mass of 12,826 Da that corresponded with the observed 12.8 kDa molecular mass obtained for M-SAA3 in immunoblot analysis. The high abundance of this extrahepatically produced SAA3 isoform in the colostrum of healthy animals suggests that M-SAA3 may play an important functional role associated with newborn adaptation to extrauterine life and possibly mammary tissue remodeling.
Original language | English (US) |
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Pages (from-to) | 203-211 |
Number of pages | 9 |
Journal | Veterinary Immunology and Immunopathology |
Volume | 83 |
Issue number | 3-4 |
DOIs | |
State | Published - 2001 |
Keywords
- Bovine cDNA
- Colostrum
- Extrahepatic serum amyloid A
- Serum amyloid A 3
ASJC Scopus subject areas
- Immunology
- veterinary(all)