Reeler 7 Jackson, a remutation of the Reln gene

Belinda Harris, Patricia Ward-Bailey, Kenneth Johnson, and Rodrick Bronson

Source of Support: This research was supported by NIH/NCRR grant RR01183 to the Mouse Mutant Resource (M.T. Davisson, PI) and Cancer Center Core Grant CA34196.

Mutation (allele) symbol: Relnrl-7J

Mutation (allele) name: Reeler 7 Jackson

Gene symbol: Relnrl-7J

Strain of origin: C57BL/6J

Current strain name: C57BL/6J-Relnrl-7J/J

Stock #: 007892 (view JAX Mice® Data Sheet for additional information including Price and Supply Information)

Phenotype categories: neurological

Abstract

We have identified a remutation of the reelin (Reln) gene by a direct test for allelism. Both the phenotype and pathology, described below, are the same as the original reeler (rl) mutation with the exception of earlier lethality in this new mutation.

Origin and Description

The spontaneous Reln<rl-7J> remutation was discovered at The Jackson Laboratory in a production colony of C57BL/6J mice by Sheila G. Haupt in 2006 and has been maintained on its original C57BL/6J background by progeny test. Mice homozygous for this recessive remutation of reeler can be recognized by two weeks of age. They have difficulty with locomotion that causes a leaning side-to-side behavior as they walk. Like original reeler homozygotes, rl-7J mutants are unable to keep their hindquaters upright and frequently fall over on their sides. To date no homozygotes have lived to adulthood. Heterozygotes for this remutation are normal.

 

Genetic Analysis

A direct test for allelism was performed by mating a homozygous C3Fe(SWV)Mbpshi-  Relnrl-5J/J female mouse to a heterozygote male carrying the new mutation. This mating produced two offspring out of ten born that were affected with the reeler phenotype, proving the new mutation to be an allele of the Reln gene.

Pathology

A routine pathological screen done on one Reln<rl-7J> mutant mouse showed neuropathology identical to the original reeler mutation (MGD 2007). The Reln<rl-7J> mouse showed scrambled layering in the cortex, neurons of the hippocampal gyrus are scattered in irregular wavy layers and the cerebellum is small with scrambled Purkinjie and granule cells.

Hearing as assessed by auditory brain stem response (ABR) testing of a homozygote male at approximately one month of age showed slightly elevated thresholds.

The eyes of a nineteen week old male homozygote were examined with an opthalamascope and were determined to be normal.

Acknowledgements

The authors thank Sheila G. Haupt for discovery of the new mutant, Norm Hawes for eye examinations, Chantal Longo Guess for ABR testing, and Coleen Marden for histological preparations.