| Primary Identifier | MGI:3042795 | Gene | Neu1 |
| Inheritance Mode | Codominant | Strain of Origin | SM/J |
| Is Recombinase | false | Is Wild Type | false |
| description | Low activity determined by the Neu1a allele occurs in the SM/J inbred strain and in wild mice in the area of Ann Arbor, Michigan; all other inbred strains have high activity determined by the Neu1b allele. Heterozygotes have intermediate activity. Neuraminidase removes extra sialic acid residues from these enzymes. The defective neuraminidase of Neu1a> mice, by failing to remove the extra sialic acid, changes their electrophoretic mobility (J:6480). Level of activity of neuraminidase in activated T lymphocytes is also depressed in Neu1a/Neu1a mice (J:7976). |
| molecularNote | Sequencing of the a allele revealed 5 nucleotide differences compared to the b allele. These changes alter the amino acid residues 11, 15, 17, 19 and 209 of the encoded protein from Gly, Tyr, Ala, Arg and Leu to Arg, Cys, Val, Cys and Ile, respectively. This encoded protein has 85-95% less activity than the protein encoded by the b allele as demonstrated in an in vitro assay. Further studies attributed most of the activity loss to the variation at position 209. Later studies detected 4 silent mutations in the signal peptide sequence and 2 mutations (c.-240C>T and c.-519G>A) in the promoter region. The mutation c.-519G>A creates a novel binding site for Nkx3-1 and Nkx3-2. In vitro assays demonstrated that binding of Nkx3-2 specifically represses promoter driven expression. |
