Abstract | BACKGROUND: RESULTS AND CONCLUSION: FACS analysis of cells carrying various PTCs surrounded by their natural neighbouring codons revealed significant reporter gene expression despite the PTC only for this patient's genetic context. Gene expression could be abolished by replacing the first or third nucleotide before, or one of the two nucleotides following the PTC. Site-directed mutagenesis was used to identify genotypes allowing PTC read-through. The genetic context of the LAMA3 mutation R943X is close to a hypothetical consensus sequence for maximum PTC read-through. Bioinformatic analysis showed that this consensus sequence is present in four sequences from the NCBI reference database, each of which contains another in-frame termination codon three or four codons apart. This indicates strong selective pressure against leaky termination codons in the human genome. This patient's mutated full length mRNA escaped nonsense-mediated decay, leading to LAMA3 mRNA levels similar to those of a healthy control, and full length laminin α3 could be detected in culture supernatant of the patient's keratinocytes. Immunofluorescence analyses of skin biopsies and continuous clinical improvement of the patient's condition suggested accumulation of intact laminin-332 in the epidermal basement membrane. These findings provide important clues for the prediction of PTC read-through in human genetic disease.
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Authors | Frederic Pacho, Giovanna Zambruno, Valentina Calabresi, Dimitra Kiritsi, Holm Schneider |
Journal | Journal of medical genetics
(J Med Genet)
Vol. 48
Issue 9
Pg. 640-4
(Sep 2011)
ISSN: 1468-6244 [Electronic] England |
PMID | 21693480
(Publication Type: Case Reports, Journal Article)
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Chemical References |
- Codon, Nonsense
- Laminin
- Nucleotides
- laminin alpha 3
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Topics |
- Alleles
- Child, Preschool
- Codon, Nonsense
- Epidermolysis Bullosa, Junctional
(genetics, metabolism)
- Fluorescent Antibody Technique
- Humans
- Laminin
(genetics)
- Male
- Nucleotides
(genetics)
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