An ENU-induced mutation in Rs1h causes disruption of retinal structure and function.
OBJECTIVE
The 44TNJ mutant mouse was generated by the Tennessee Mouse Genome Consortium (TMGC) using an ENU-based mutagenesis screen to produce recessive mutations that affect the eye and brain. Herein we present its retinal phenotype and genetic basis.


METHODS
Fourth generation offspring (G4) and confirmed mutants were examined using slit lamp biomicroscopy, funduscopy, histology, immunohistochemistry, and electroretinography (ERG). 44TNJ mutant mice were crossed to C3BLiA or DBA/2 mice for chromosomal mapping purposes. Linkage analysis by PCR-based microsatellite marker genotyping was used to identify the disease locus. The Rs1h cDNA and its genomic DNA were sequenced directly.


RESULTS
The 44TNJ pedigree was the first mutant pedigree identified by the ocular phenotyping domain of the TMGC. Examination of the fundus revealed numerous small and homogeneous intraretinal microflecks in the peripapillary region, which became courser and more irregular in the periphery. Males were typically more affected than females. Histology and immunohistochemistry revealed a disruption of the lamination of the retina, particularly at both margins of the outer nuclear layer, along with reduced calbindin immunostaining. ERG analyses revealed reduced amplitudes of both a-waves and b-waves. Linkage analysis mapped the 44TNJ mutation to the X chromosome close to the marker DXMit117. Sequence analysis of the positional candidate gene Rs1h revealed a T->C exchange at the second base of intron 2 of the Rs1h gene.


CONCLUSIONS
We have generated and characterized a mutant mouse line that was produced using ENU-based mutagenesis. The 44TNJ pedigree manifests with photoreceptor dysfunction and concurrent structural and functional aberrations at the post-receptoral level. Genetic analysis revealed a mutation in Rs1h, making this the first murine model of X-linked retinoschisis in which the gene is expressed.
Jablonski
Monica M
MM
Department of Ophthalmology, University of Tennessee Health Science Center and Tennessee Mouse Genome Consortium, Memphis, TN, USA. mjablonski@utmem.edu
Dalke
Claudia
C
Wang
XiaoFei
X
Lu
Lu
L
Manly
Kenneth F
KF
Pretsch
Walter
W
Favor
Jack
J
Pardue
Machelle T
MT
Rinchik
Eugene M
EM
Williams
Robert W
RW
Goldowitz
Daniel
D
Graw
Jochen
J
D000477:Alkylating Agents / Q000633:toxicity*; D000818:Animals; D001483:Base Sequence; D015815:Cell Adhesion Molecules / Q000235:genetics*; D002874:Chromosome Mapping; D004252:DNA Mutational Analysis; D004195:Disease Models, Animal; D004596:Electroretinography; D005038:Ethylnitrosourea / Q000633:toxicity*; D005136:Eye Proteins / Q000235:genetics*; D005260:Female; D007124:Immunoenzyme Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008817:Mice, Mutant Strains; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation / Q000187:drug effects*; D012160:Retina / Q000503:physiopathology*; D041441:Retinoschisis / Q000235:genetics* / Q000503:physiopathology
D000477:Alkylating Agents; D015815:Cell Adhesion Molecules; D005136:Eye Proteins; C491843:RS1 protein, mouse; D005038:Ethylnitrosourea