International Mammalian Genome Society

logo18th International Mouse Genome Conference

17-22 October 2004, Seattle, USA


POSTER 71 - BEHAVIORAL CHARACTERIZATION AND LINKAGE ANALYSIS OF AN ENU-INDUCED MOUSE MUTANT LINE THAT SHOWS LEARNING DEFICIT, REDUCTION OF BODY SIZE, CONVULSIVE SEIZURE, AND TRANSIENT IMMOBILITY

Furuse T, Wada Y, Masuya H, Kaneda H, Kobayashi K, Kawai A, Kushida T, Nishii R, Gondo Y, Noda T, Wakana S, Shiroishi T

RIKEN GSC, Tsukuba, Japan

We are carrying out a large-scale screening for behavioral mutant mice induced by ENU. A mutant line designated as M100200 was identified in the screening, and showed learning deficit in the passive avoidance test. In further analysis, three characteristic phenotypes, reduction of body size, convulsive seizure, and immobility were observed in the backcross progeny. In-depth characterization indicated reduction of body weight, short body length, and small body mass index specifically in the male mice. The convulsive seizure and immobility start suddenly with vocalization, ataxic gait, lowered posture and slow movement. The symptom starts 30-60 minutes after mice were transferred to new home cage. When the mutants are immobilized, they continuously open their eyes, sometimes move their vibrissae, and show prayer reflex. They move a few steps in response to human contact. Thus, affected mutant mice keep conscious during immobility. A single dominant mutation may cause the multiple symptoms in M100200 line, because the several symptoms are co-segregated in the back-cross progeny (N6). To identify the causative gene, we carried out linkage analysis. Backcross progeny was phenotyped for the immobility and genotyped for SNPs markers. As a result, the causative gene was mapped to chromosome 4. Further fine mapping and detailed behavioral characterization are now underway.

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