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Tight junctions in Schwann cells of peripheral myelinated axons: a lesson from claudin-19-deficient mice.

Miyamoto T, Morita K, Takemoto D, Takeuchi K, Kitano Y, Miyakawa T, Nakayama K, Okamura Y, Sasaki H, Miyachi Y, Furuse M, Tsukita S - J. Cell Biol. (2005)

Bottom Line: Claudin-19-deficient mice were generated, and they exhibited behavioral abnormalities that could be attributed to peripheral nervous system deficits.Interestingly, the overall morphology of Schwann cells lacking claudin-19 expression appeared to be normal not only in the internodal region but also at the node of Ranvier, except that TJs completely disappeared, at least from the outer/inner mesaxons.These findings have indicated that, similar to epithelial cells, Schwann cells also bear claudin-based TJs, and they have also suggested that these TJs are not involved in the polarized morphogenesis but are involved in the electrophysiological "sealing" function of Schwann cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Graduate School of Medicine, Kyoto University, Japan.

ABSTRACT
Tight junction (TJ)-like structures have been reported in Schwann cells, but their molecular composition and physiological function remain elusive. We found that claudin-19, a novel member of the claudin family (TJ adhesion molecules in epithelia), constituted these structures. Claudin-19-deficient mice were generated, and they exhibited behavioral abnormalities that could be attributed to peripheral nervous system deficits. Electrophysiological analyses showed that the claudin-19 deficiency affected the nerve conduction of peripheral myelinated fibers. Interestingly, the overall morphology of Schwann cells lacking claudin-19 expression appeared to be normal not only in the internodal region but also at the node of Ranvier, except that TJs completely disappeared, at least from the outer/inner mesaxons. These findings have indicated that, similar to epithelial cells, Schwann cells also bear claudin-based TJs, and they have also suggested that these TJs are not involved in the polarized morphogenesis but are involved in the electrophysiological "sealing" function of Schwann cells.

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Generation of claudin-19–deficient mice. (A) Construction of the wild-type allele, the targeting vector, and the targeted allele of the mouse claudin-19 gene. Four exons covered the whole ORF of claudin-19, and the targeting vector contained the pgk-neo cassette in its middle portion to delete all of these exons in the targeted allele. The position of the probe for Southern blotting is indicated as a bar. MC1pDT-A, diphthelia toxin A expression cassette; X, XbaI; B, BamHI. (B) Genotype analyses by Southern blotting of XbaI-digested genomic DNA from wild-type (+/+), heterozygous (+/−), and homozygous (−/−) mice for the mutant claudin-19 gene allele. Southern blotting with the probe (A) yielded a 10-kb and a 6.5-kb band from the wild-type and targeted allele, respectively. (C) Loss of claudin-19 mRNA in the kidney of claudin-19–deficient mice examined by RT-PCR. As a control, the hypoxanthine phosphoribosyl transferase gene was equally amplified in all samples.
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fig3: Generation of claudin-19–deficient mice. (A) Construction of the wild-type allele, the targeting vector, and the targeted allele of the mouse claudin-19 gene. Four exons covered the whole ORF of claudin-19, and the targeting vector contained the pgk-neo cassette in its middle portion to delete all of these exons in the targeted allele. The position of the probe for Southern blotting is indicated as a bar. MC1pDT-A, diphthelia toxin A expression cassette; X, XbaI; B, BamHI. (B) Genotype analyses by Southern blotting of XbaI-digested genomic DNA from wild-type (+/+), heterozygous (+/−), and homozygous (−/−) mice for the mutant claudin-19 gene allele. Southern blotting with the probe (A) yielded a 10-kb and a 6.5-kb band from the wild-type and targeted allele, respectively. (C) Loss of claudin-19 mRNA in the kidney of claudin-19–deficient mice examined by RT-PCR. As a control, the hypoxanthine phosphoribosyl transferase gene was equally amplified in all samples.

Mentions: To explore the function of claudin-19 in vivo, we produced mice unable to express it. Nucleotide sequencing, as well as restriction mapping, identified four exons that cover the whole ORF of claudin-19 (Fig. 3 A). We constructed a targeting vector, which was designed to disrupt the claudin-19 gene by replacing all of these exons (exons 1–4) with the neomycin resistance gene. Two distinct lines of mice were generated from distinct embryonic stem (ES) cell clones in which the claudin-19 gene was disrupted by homologous recombination. Southern blotting confirmed the disruption of the claudin-19 gene in heterozygous as well as in homozygous mutant mice (Fig. 3 B), and RT-PCR detected no claudin-19 mRNA from the kidney of homozygous mutant mice (Fig. 3 C). Because both lines of mice showed the same phenotypes, we will mainly present data obtained from one line.


Tight junctions in Schwann cells of peripheral myelinated axons: a lesson from claudin-19-deficient mice.

Miyamoto T, Morita K, Takemoto D, Takeuchi K, Kitano Y, Miyakawa T, Nakayama K, Okamura Y, Sasaki H, Miyachi Y, Furuse M, Tsukita S - J. Cell Biol. (2005)

Generation of claudin-19–deficient mice. (A) Construction of the wild-type allele, the targeting vector, and the targeted allele of the mouse claudin-19 gene. Four exons covered the whole ORF of claudin-19, and the targeting vector contained the pgk-neo cassette in its middle portion to delete all of these exons in the targeted allele. The position of the probe for Southern blotting is indicated as a bar. MC1pDT-A, diphthelia toxin A expression cassette; X, XbaI; B, BamHI. (B) Genotype analyses by Southern blotting of XbaI-digested genomic DNA from wild-type (+/+), heterozygous (+/−), and homozygous (−/−) mice for the mutant claudin-19 gene allele. Southern blotting with the probe (A) yielded a 10-kb and a 6.5-kb band from the wild-type and targeted allele, respectively. (C) Loss of claudin-19 mRNA in the kidney of claudin-19–deficient mice examined by RT-PCR. As a control, the hypoxanthine phosphoribosyl transferase gene was equally amplified in all samples.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2171943&req=5

fig3: Generation of claudin-19–deficient mice. (A) Construction of the wild-type allele, the targeting vector, and the targeted allele of the mouse claudin-19 gene. Four exons covered the whole ORF of claudin-19, and the targeting vector contained the pgk-neo cassette in its middle portion to delete all of these exons in the targeted allele. The position of the probe for Southern blotting is indicated as a bar. MC1pDT-A, diphthelia toxin A expression cassette; X, XbaI; B, BamHI. (B) Genotype analyses by Southern blotting of XbaI-digested genomic DNA from wild-type (+/+), heterozygous (+/−), and homozygous (−/−) mice for the mutant claudin-19 gene allele. Southern blotting with the probe (A) yielded a 10-kb and a 6.5-kb band from the wild-type and targeted allele, respectively. (C) Loss of claudin-19 mRNA in the kidney of claudin-19–deficient mice examined by RT-PCR. As a control, the hypoxanthine phosphoribosyl transferase gene was equally amplified in all samples.
Mentions: To explore the function of claudin-19 in vivo, we produced mice unable to express it. Nucleotide sequencing, as well as restriction mapping, identified four exons that cover the whole ORF of claudin-19 (Fig. 3 A). We constructed a targeting vector, which was designed to disrupt the claudin-19 gene by replacing all of these exons (exons 1–4) with the neomycin resistance gene. Two distinct lines of mice were generated from distinct embryonic stem (ES) cell clones in which the claudin-19 gene was disrupted by homologous recombination. Southern blotting confirmed the disruption of the claudin-19 gene in heterozygous as well as in homozygous mutant mice (Fig. 3 B), and RT-PCR detected no claudin-19 mRNA from the kidney of homozygous mutant mice (Fig. 3 C). Because both lines of mice showed the same phenotypes, we will mainly present data obtained from one line.

Bottom Line: Claudin-19-deficient mice were generated, and they exhibited behavioral abnormalities that could be attributed to peripheral nervous system deficits.Interestingly, the overall morphology of Schwann cells lacking claudin-19 expression appeared to be normal not only in the internodal region but also at the node of Ranvier, except that TJs completely disappeared, at least from the outer/inner mesaxons.These findings have indicated that, similar to epithelial cells, Schwann cells also bear claudin-based TJs, and they have also suggested that these TJs are not involved in the polarized morphogenesis but are involved in the electrophysiological "sealing" function of Schwann cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Graduate School of Medicine, Kyoto University, Japan.

ABSTRACT
Tight junction (TJ)-like structures have been reported in Schwann cells, but their molecular composition and physiological function remain elusive. We found that claudin-19, a novel member of the claudin family (TJ adhesion molecules in epithelia), constituted these structures. Claudin-19-deficient mice were generated, and they exhibited behavioral abnormalities that could be attributed to peripheral nervous system deficits. Electrophysiological analyses showed that the claudin-19 deficiency affected the nerve conduction of peripheral myelinated fibers. Interestingly, the overall morphology of Schwann cells lacking claudin-19 expression appeared to be normal not only in the internodal region but also at the node of Ranvier, except that TJs completely disappeared, at least from the outer/inner mesaxons. These findings have indicated that, similar to epithelial cells, Schwann cells also bear claudin-based TJs, and they have also suggested that these TJs are not involved in the polarized morphogenesis but are involved in the electrophysiological "sealing" function of Schwann cells.

Show MeSH
Related in: MedlinePlus