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Different human copper-zinc superoxide dismutase mutants, SOD1G93A and SOD1H46R, exert distinct harmful effects on gross phenotype in mice.

Pan L, Yoshii Y, Otomo A, Ogawa H, Iwasaki Y, Shang HF, Hadano S - PLoS ONE (2012)

Bottom Line: Copy number of the transgene and their expression between SOD1(G93A) and SOD1(H46R) lines were comparable.B6 congenic mutant SOD1 transgenic lines irrespective of their mutation and gender differences lived longer than corresponding FVB lines.These results indicate that SOD1(G93A)- and SOD1(H46R)-mediated toxicity and their associated pathogenic pathways are not identical.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Life Sciences, Tokai University School of Medicine, Isehara, Kanagawa, Japan.

ABSTRACT
Amyotrophic lateral sclerosis (ALS) is a heterogeneous group of fatal neurodegenerative diseases characterized by a selective loss of motor neurons in the brain and spinal cord. Creation of transgenic mice expressing mutant Cu/Zn superoxide dismutase (SOD1), as ALS models, has made an enormous impact on progress of the ALS studies. Recently, it has been recognized that genetic background and gender affect many physiological and pathological phenotypes. However, no systematic studies focusing on such effects using ALS models other than SOD1(G93A) mice have been conducted. To clarify the effects of genetic background and gender on gross phenotypes among different ALS models, we here conducted a comparative analysis of growth curves and lifespans using congenic lines of SOD1(G93A) and SOD1(H46R) mice on two different genetic backgrounds; C57BL/6N (B6) and FVB/N (FVB). Copy number of the transgene and their expression between SOD1(G93A) and SOD1(H46R) lines were comparable. B6 congenic mutant SOD1 transgenic lines irrespective of their mutation and gender differences lived longer than corresponding FVB lines. Notably, the G93A mutation caused severer disease phenotypes than did the H46R mutation, where SOD1(G93A) mice, particularly on a FVB background, showed more extensive body weight loss and earlier death. Gender effect on survival also solely emerged in FVB congenic SOD1(G93A) mice. Conversely, consistent with our previous study using B6 lines, lack of Als2, a murine homolog for the recessive juvenile ALS causative gene, in FVB congenic SOD1(H46R), but not SOD1(G93A), mice resulted in an earlier death, implying a genetic background-independent but mutation-dependent phenotypic modification. These results indicate that SOD1(G93A)- and SOD1(H46R)-mediated toxicity and their associated pathogenic pathways are not identical. Further, distinctive injurious effects resulted from different SOD1 mutations, which are associated with genetic background and/or gender, suggests the presence of several genetic modifiers of disease expression in the mouse genome.

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Copy numbers of the transgene and the levels of its transcript.(A) Comparison of the difference in threshold cycle (ΔCT) between the human SOD1 transgene (SOD1) and a reference mouse Sod1 gene (Sod1) in SOD1G93A and SOD1H46R transgenic mice. There are no significant differences in the mean values between groups with different genders (F; female, M; male), genotypes (G93A; SOD1G93A, H46R; SOD1H46R), and genetic backgrounds (B6; C57BL/6, FVB; FVB/N). (B) Comparison of the ΔCT between the human SOD1 and the mouse Actb transcripts in SOD1G93A and SOD1H46R transgenic mice. There are no significant differences in the mean values between groups with different genders, genotypes, and genetic backgrounds. All values are mean ± SD (n = 4). Statistical significance is evaluated by ANOVA with Bonferroni's post hoc test.
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pone-0033409-g001: Copy numbers of the transgene and the levels of its transcript.(A) Comparison of the difference in threshold cycle (ΔCT) between the human SOD1 transgene (SOD1) and a reference mouse Sod1 gene (Sod1) in SOD1G93A and SOD1H46R transgenic mice. There are no significant differences in the mean values between groups with different genders (F; female, M; male), genotypes (G93A; SOD1G93A, H46R; SOD1H46R), and genetic backgrounds (B6; C57BL/6, FVB; FVB/N). (B) Comparison of the ΔCT between the human SOD1 and the mouse Actb transcripts in SOD1G93A and SOD1H46R transgenic mice. There are no significant differences in the mean values between groups with different genders, genotypes, and genetic backgrounds. All values are mean ± SD (n = 4). Statistical significance is evaluated by ANOVA with Bonferroni's post hoc test.

Mentions: In this study, we generated four independent congenic mouse lines expressing the human mutated SOD1 gene; i.e., C57BL/6N congenic SOD1G93A (B6_G93A) and SOD1H46R (B6_H46R), and FVB/N congenic SOD1G93A (FVB_ G93A) and SOD1H46R (FVB_ H46R). The transgene in each mouse line was transmitted in the expected Mendelian ratio of an autosomal gene (data not shown). The previous studies have demonstrated that the estimated copy numbers of SOD1G93A and SOD1H46R in original transgenic lines are approximately 24 [14] and 20 [23], respectively. Since it has been shown that a copy number of the mutated SOD1 transgene affects the disease severity [14], we first analyzed the copy numbers of the transgene in our mouse lines by quantitative PCR. The relative number of transgene's copy was estimated by the difference in threshold cycle (ΔCT, delta CT) between the transgene (SOD1G93A or SOD1H46R) and control (mouse Sod1). There were no significant differences in the ΔCT values among all four lines with different transgenes, genetic backgrounds, and/or genders (Figure 1A and Table 1). These results indicate that each transgene locus retains comparable number of the mutated SOD1 gene that is stably transmitted in the course of generating our congenic lines, and that the copy numbers of the transgene between SOD1G93A and SOD1H46R are almost equal.


Different human copper-zinc superoxide dismutase mutants, SOD1G93A and SOD1H46R, exert distinct harmful effects on gross phenotype in mice.

Pan L, Yoshii Y, Otomo A, Ogawa H, Iwasaki Y, Shang HF, Hadano S - PLoS ONE (2012)

Copy numbers of the transgene and the levels of its transcript.(A) Comparison of the difference in threshold cycle (ΔCT) between the human SOD1 transgene (SOD1) and a reference mouse Sod1 gene (Sod1) in SOD1G93A and SOD1H46R transgenic mice. There are no significant differences in the mean values between groups with different genders (F; female, M; male), genotypes (G93A; SOD1G93A, H46R; SOD1H46R), and genetic backgrounds (B6; C57BL/6, FVB; FVB/N). (B) Comparison of the ΔCT between the human SOD1 and the mouse Actb transcripts in SOD1G93A and SOD1H46R transgenic mice. There are no significant differences in the mean values between groups with different genders, genotypes, and genetic backgrounds. All values are mean ± SD (n = 4). Statistical significance is evaluated by ANOVA with Bonferroni's post hoc test.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3306410&req=5

pone-0033409-g001: Copy numbers of the transgene and the levels of its transcript.(A) Comparison of the difference in threshold cycle (ΔCT) between the human SOD1 transgene (SOD1) and a reference mouse Sod1 gene (Sod1) in SOD1G93A and SOD1H46R transgenic mice. There are no significant differences in the mean values between groups with different genders (F; female, M; male), genotypes (G93A; SOD1G93A, H46R; SOD1H46R), and genetic backgrounds (B6; C57BL/6, FVB; FVB/N). (B) Comparison of the ΔCT between the human SOD1 and the mouse Actb transcripts in SOD1G93A and SOD1H46R transgenic mice. There are no significant differences in the mean values between groups with different genders, genotypes, and genetic backgrounds. All values are mean ± SD (n = 4). Statistical significance is evaluated by ANOVA with Bonferroni's post hoc test.
Mentions: In this study, we generated four independent congenic mouse lines expressing the human mutated SOD1 gene; i.e., C57BL/6N congenic SOD1G93A (B6_G93A) and SOD1H46R (B6_H46R), and FVB/N congenic SOD1G93A (FVB_ G93A) and SOD1H46R (FVB_ H46R). The transgene in each mouse line was transmitted in the expected Mendelian ratio of an autosomal gene (data not shown). The previous studies have demonstrated that the estimated copy numbers of SOD1G93A and SOD1H46R in original transgenic lines are approximately 24 [14] and 20 [23], respectively. Since it has been shown that a copy number of the mutated SOD1 transgene affects the disease severity [14], we first analyzed the copy numbers of the transgene in our mouse lines by quantitative PCR. The relative number of transgene's copy was estimated by the difference in threshold cycle (ΔCT, delta CT) between the transgene (SOD1G93A or SOD1H46R) and control (mouse Sod1). There were no significant differences in the ΔCT values among all four lines with different transgenes, genetic backgrounds, and/or genders (Figure 1A and Table 1). These results indicate that each transgene locus retains comparable number of the mutated SOD1 gene that is stably transmitted in the course of generating our congenic lines, and that the copy numbers of the transgene between SOD1G93A and SOD1H46R are almost equal.

Bottom Line: Copy number of the transgene and their expression between SOD1(G93A) and SOD1(H46R) lines were comparable.B6 congenic mutant SOD1 transgenic lines irrespective of their mutation and gender differences lived longer than corresponding FVB lines.These results indicate that SOD1(G93A)- and SOD1(H46R)-mediated toxicity and their associated pathogenic pathways are not identical.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Life Sciences, Tokai University School of Medicine, Isehara, Kanagawa, Japan.

ABSTRACT
Amyotrophic lateral sclerosis (ALS) is a heterogeneous group of fatal neurodegenerative diseases characterized by a selective loss of motor neurons in the brain and spinal cord. Creation of transgenic mice expressing mutant Cu/Zn superoxide dismutase (SOD1), as ALS models, has made an enormous impact on progress of the ALS studies. Recently, it has been recognized that genetic background and gender affect many physiological and pathological phenotypes. However, no systematic studies focusing on such effects using ALS models other than SOD1(G93A) mice have been conducted. To clarify the effects of genetic background and gender on gross phenotypes among different ALS models, we here conducted a comparative analysis of growth curves and lifespans using congenic lines of SOD1(G93A) and SOD1(H46R) mice on two different genetic backgrounds; C57BL/6N (B6) and FVB/N (FVB). Copy number of the transgene and their expression between SOD1(G93A) and SOD1(H46R) lines were comparable. B6 congenic mutant SOD1 transgenic lines irrespective of their mutation and gender differences lived longer than corresponding FVB lines. Notably, the G93A mutation caused severer disease phenotypes than did the H46R mutation, where SOD1(G93A) mice, particularly on a FVB background, showed more extensive body weight loss and earlier death. Gender effect on survival also solely emerged in FVB congenic SOD1(G93A) mice. Conversely, consistent with our previous study using B6 lines, lack of Als2, a murine homolog for the recessive juvenile ALS causative gene, in FVB congenic SOD1(H46R), but not SOD1(G93A), mice resulted in an earlier death, implying a genetic background-independent but mutation-dependent phenotypic modification. These results indicate that SOD1(G93A)- and SOD1(H46R)-mediated toxicity and their associated pathogenic pathways are not identical. Further, distinctive injurious effects resulted from different SOD1 mutations, which are associated with genetic background and/or gender, suggests the presence of several genetic modifiers of disease expression in the mouse genome.

Show MeSH
Related in: MedlinePlus