Electrophoretic analysis of liver neuraminidase-1 variation in mice and additional evidence concerning the location of NEU-1.
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Neuraminidase-1 (NEU-1) is one of two neuraminidase isozymes which can be detected electrophoretically in mouse liver extracts. The inheritance of variation in NEU-1 and the linkage relationships of the gene controlling this variation were studied through a backcross analysis involving the SM/J and MA/MyJ inbred strains, and by examination of NEU-1 phenotypes in three congenic strains: B10.SM, B10.SM(22R) and B10.RVB. The data indicate that NEU-1 is controlled by Neu-1, a gene previously identified by its effect on total liver neuraminidase activity in whole tissue homogenates. Analysis of the congenic strains revealed identical low activity (SM/J-type: Neu-1a/Neu-1a) NEU-1 phenotypes in all three strains. This indicates that Neu-1 lies in the segment of the SM/J-derived H-2 region that is common to all three strains: H-2E alpha to H-2D. In addition, we examined the relationship between NEU-1 and phenotypic variation in liver acid phosphatase (AP; for which a new typing method is described) and linkage order among several other enzyme-coding genes linked to H-2. In all animals that could be scored confidently for AP, the NEU-1 and AP phenotypes were concordant, adding support to the hypothesis that both phenotypes are controlled by Neu-1. Recombination rates among six H-2-linked marker loci were unexpectedly low, but were sufficient to verify the position of Upg-1 as the telomeric flanking marker relative to Glo-1, H-2 (C4), Neu-1 (Apl), Ce-2 and Pgk-2.