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Regulated splicing of the fibronectin EDA exon is essential for proper skin wound healing and normal lifespan.

Muro AF, Chauhan AK, Gajovic S, Iaconcig A, Porro F, Stanta G, Baralle FE - J. Cell Biol. (2003)

Bottom Line: However, the precise role of the FN isoforms is poorly understood.One of the alternatively spliced exons is the extra domain A (EDA) or extra type III homology that is regulated spatially and temporally during development and aging.Constitutive exon inclusion was obtained by optimizing the splice sites, whereas complete exclusion was obtained after in vivo CRE-loxP-mediated deletion of the exon.

View Article: PubMed Central - PubMed

Affiliation: International Center for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34012 Trieste, Italy.

ABSTRACT
Fibronectins (FNs) are multifunctional high molecular weight glycoproteins present in the blood plasma and in the ECMs of tissues. The FN primary transcript undergoes alternative splicing in three regions generating up to 20 main different variants in humans. However, the precise role of the FN isoforms is poorly understood. One of the alternatively spliced exons is the extra domain A (EDA) or extra type III homology that is regulated spatially and temporally during development and aging. To study its in vivo function, we generated mice devoid of EDA exon-regulated splicing. Constitutive exon inclusion was obtained by optimizing the splice sites, whereas complete exclusion was obtained after in vivo CRE-loxP-mediated deletion of the exon. Homozygous mouse strains with complete exclusion or inclusion of the EDA exon were viable and developed normally, indicating that the alternative splicing at the EDA exon is not necessary during embryonic development. Conversely, mice without the EDA exon in the FN protein displayed abnormal skin wound healing, whereas mice having constitutive inclusion of the EDA exon showed a major decrease in the FN levels in all tissues. Moreover, both mutant mouse strains have a significantly shorter lifespan than the control mice, suggesting that EDA splicing regulation is necessary for efficient long-term maintenance of biological functions.

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Related in: MedlinePlus

The lack of alternative splicing of the EDA exon reduces the lifespan of mutant mice. Both EDA+/+ and EDA−/− mice showed a reduced lifespan during the 30-mo period of analysis. The graphic shows a Kaplan-Meier representation of the survival versus time of 39, 45, and 53 EDAwt/wt, EDA+/+, and EDA−/− mice, respectively, that were housed in individual cages throughout the study. The results were analyzed with the Log-rank test and both the EDA+/+ and the EDA−/− curves were statistically significant when compared with the EDAwt/wt mice (indicated by asterisks, P ≤ 0.0005).
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fig7: The lack of alternative splicing of the EDA exon reduces the lifespan of mutant mice. Both EDA+/+ and EDA−/− mice showed a reduced lifespan during the 30-mo period of analysis. The graphic shows a Kaplan-Meier representation of the survival versus time of 39, 45, and 53 EDAwt/wt, EDA+/+, and EDA−/− mice, respectively, that were housed in individual cages throughout the study. The results were analyzed with the Log-rank test and both the EDA+/+ and the EDA−/− curves were statistically significant when compared with the EDAwt/wt mice (indicated by asterisks, P ≤ 0.0005).

Mentions: The in vivo studies performed on rats show a critical decrease in EDA+/EDA− ratio after birth, with an additional gradual decrease of the ratio in some tissues that is correlated with the age of the animal (Magnuson et al., 1991; Pagani et al., 1991). We addressed the question if in EDA+/+ and EDA−/− mice, having no regulation of EDA splicing, the presence or absence of the EDA exon could have an effect on their lifespan. For this purpose, we performed a long-term experiment using 139 mice (EDAwt/wt, n = 39; EDA+/+, n = 47; and EDA−/−n = 53) that were caged separately throughout the experiment and the time of animal death was recorded. The Kaplan-Meier graphical representation of the data is shown in Fig. 7Figure 7.


Regulated splicing of the fibronectin EDA exon is essential for proper skin wound healing and normal lifespan.

Muro AF, Chauhan AK, Gajovic S, Iaconcig A, Porro F, Stanta G, Baralle FE - J. Cell Biol. (2003)

The lack of alternative splicing of the EDA exon reduces the lifespan of mutant mice. Both EDA+/+ and EDA−/− mice showed a reduced lifespan during the 30-mo period of analysis. The graphic shows a Kaplan-Meier representation of the survival versus time of 39, 45, and 53 EDAwt/wt, EDA+/+, and EDA−/− mice, respectively, that were housed in individual cages throughout the study. The results were analyzed with the Log-rank test and both the EDA+/+ and the EDA−/− curves were statistically significant when compared with the EDAwt/wt mice (indicated by asterisks, P ≤ 0.0005).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2172721&req=5

fig7: The lack of alternative splicing of the EDA exon reduces the lifespan of mutant mice. Both EDA+/+ and EDA−/− mice showed a reduced lifespan during the 30-mo period of analysis. The graphic shows a Kaplan-Meier representation of the survival versus time of 39, 45, and 53 EDAwt/wt, EDA+/+, and EDA−/− mice, respectively, that were housed in individual cages throughout the study. The results were analyzed with the Log-rank test and both the EDA+/+ and the EDA−/− curves were statistically significant when compared with the EDAwt/wt mice (indicated by asterisks, P ≤ 0.0005).
Mentions: The in vivo studies performed on rats show a critical decrease in EDA+/EDA− ratio after birth, with an additional gradual decrease of the ratio in some tissues that is correlated with the age of the animal (Magnuson et al., 1991; Pagani et al., 1991). We addressed the question if in EDA+/+ and EDA−/− mice, having no regulation of EDA splicing, the presence or absence of the EDA exon could have an effect on their lifespan. For this purpose, we performed a long-term experiment using 139 mice (EDAwt/wt, n = 39; EDA+/+, n = 47; and EDA−/−n = 53) that were caged separately throughout the experiment and the time of animal death was recorded. The Kaplan-Meier graphical representation of the data is shown in Fig. 7Figure 7.

Bottom Line: However, the precise role of the FN isoforms is poorly understood.One of the alternatively spliced exons is the extra domain A (EDA) or extra type III homology that is regulated spatially and temporally during development and aging.Constitutive exon inclusion was obtained by optimizing the splice sites, whereas complete exclusion was obtained after in vivo CRE-loxP-mediated deletion of the exon.

View Article: PubMed Central - PubMed

Affiliation: International Center for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34012 Trieste, Italy.

ABSTRACT
Fibronectins (FNs) are multifunctional high molecular weight glycoproteins present in the blood plasma and in the ECMs of tissues. The FN primary transcript undergoes alternative splicing in three regions generating up to 20 main different variants in humans. However, the precise role of the FN isoforms is poorly understood. One of the alternatively spliced exons is the extra domain A (EDA) or extra type III homology that is regulated spatially and temporally during development and aging. To study its in vivo function, we generated mice devoid of EDA exon-regulated splicing. Constitutive exon inclusion was obtained by optimizing the splice sites, whereas complete exclusion was obtained after in vivo CRE-loxP-mediated deletion of the exon. Homozygous mouse strains with complete exclusion or inclusion of the EDA exon were viable and developed normally, indicating that the alternative splicing at the EDA exon is not necessary during embryonic development. Conversely, mice without the EDA exon in the FN protein displayed abnormal skin wound healing, whereas mice having constitutive inclusion of the EDA exon showed a major decrease in the FN levels in all tissues. Moreover, both mutant mouse strains have a significantly shorter lifespan than the control mice, suggesting that EDA splicing regulation is necessary for efficient long-term maintenance of biological functions.

Show MeSH
Related in: MedlinePlus