Dataset Information

The severity of retinal degeneration in Rp1h gene-targeted mice is dependent on genetic background.

ABSTRACT:

Purpose

The severity of disease in patients with retinitis pigmentosa (RP) can vary significantly, even among patients with the same primary mutations. It is hypothesized that modifier genes play important roles in determining the severity of RP, including the retinitis pigmentosa 1 (RP1) form of disease. To investigate the basis of variation in disease expression for RP1 disease, the authors generated congenic mice with a gene-targeted retinitis pigmentosa 1 homolog (Rp1h) allele (Rp1h(tm1Eap)) on several different genetic backgrounds and analyzed their retinal phenotypes.

Methods

The Rp1h(tm1Eap) allele was placed onto the C57BL/6J, DBA1/J, and A/J backgrounds. Retinal function of the resultant congenic mice was evaluated using electroretinographic analyses. Retinal structure and ultrastructure were evaluated using light and electron microscopy. Rp1h protein location was determined with immunofluorescence microscopy.

Results

Analysis of the retinal phenotype of incipient congenic (N6) B6.129S-Rp1h(+/tm1Eap), DBA.129S(B6)-Rp1h(+/tm1Eap), and A.129S(B6)-Rp1h(+/tm1Eap) mice at 1 year of age showed retinal degeneration only in the A.129S(B6)-Rp1h(+/tm1Eap) mice. Further analyses revealed that the photoreceptors of the fully congenic A.129S(B6)-Rp1h(+/tm1Eap) mice show evidence of degeneration at 6 months of age and are almost completely lost by 18 months of age. In contrast, the photoreceptor cells in the fully congenic B6.129S-Rp1h(+/tm1Eap) mice remain healthy up to 18 months.

Conclusions

The severity of the retinal degeneration caused by the Rp1h(tm1Eap) allele is notably dependent on genetic background. The development and characterization of the B6.129S-Rp1h(+/tm1Eap) and A.129S(B6)-Rp1h(+/tm1Eap) congenic mouse lines will facilitate identification of sequence alterations in genes that modify the severity of RP1 disease.

SUBMITTER: Liu Q

PROVIDER: S-EPMC2701263 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature

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Publications

The severity of retinal degeneration in Rp1h gene-targeted mice is dependent on genetic background.

Liu Qin Q Saveliev Alexei A Pierce Eric A EA

Investigative ophthalmology & visual science 20081205 4

<h4>Purpose</h4>The severity of disease in patients with retinitis pigmentosa (RP) can vary significantly, even among patients with the same primary mutations. It is hypothesized that modifier genes play important roles in determining the severity of RP, including the retinitis pigmentosa 1 (RP1) form of disease. To investigate the basis of variation in disease expression for RP1 disease, the authors generated congenic mice with a gene-targeted retinitis pigmentosa 1 homolog (Rp1h) allele (Rp1h( ...[more]

PMID: 19060274

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Project description:AimsPatients with mutations in SCN5A encoding NaV1.5 often display variable severity of electrical and structural alterations, but the underlying mechanisms are not fully elucidated. We here investigate the combined modulatory effect of genetic background and age on disease severity in the Scn5a1798insD/+ mouse model.Methods and resultsIn vivo electrocardiogram and echocardiograms, ex vivo electrical and optical mapping, and histological analyses were performed in adult (2-7 months) and aged (8-28 months) wild-type (WT) and Scn5a1798insD/+ (mutant, MUT) mice from the FVB/N and 129P2 inbred strains. Atrio-ventricular (AV) conduction, ventricular conduction, and ventricular repolarization are modulated by strain, genotype, and age. An aging effect was present in MUT mice, with aged MUT mice of both strains showing prolonged QRS interval and right ventricular (RV) conduction slowing. 129P2-MUT mice were severely affected, with adult and aged 129P2-MUT mice displaying AV and ventricular conduction slowing, prolonged repolarization, and spontaneous arrhythmias. In addition, the 129P2 strain appeared particularly susceptible to age-dependent electrical, functional, and structural alterations including RV conduction slowing, reduced left ventricular (LV) ejection fraction, RV dilatation, and myocardial fibrosis as compared to FVB/N mice. Overall, aged 129P2-MUT mice displayed the most severe conduction defects, RV dilatation, and myocardial fibrosis, in addition to the highest frequency of spontaneous arrhythmia and inducible arrhythmias.ConclusionGenetic background and age both modulate disease severity in Scn5a1798insD/+ mice and hence may explain, at least in part, the variable disease expressivity observed in patients with SCN5A mutations. Age- and genetic background-dependent development of cardiac structural alterations furthermore impacts arrhythmia risk. Our findings therefore emphasize the importance of continued assessment of cardiac structure and function in patients carrying SCN5A mutations.

Dataset Information

The severity of retinal degeneration in Rp1h gene-targeted mice is dependent on genetic background.

Purpose

Methods

Results

Conclusions

Publications

The severity of retinal degeneration in Rp1h gene-targeted mice is dependent on genetic background.

Similar Datasets

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