Αρχειοθήκη ιστολογίου

Αλέξανδρος Γ. Σφακιανάκης
ΩτοΡινοΛαρυγγολόγος
Αναπαύσεως 5
Άγιος Νικόλαος Κρήτη 72100
2841026182
6032607174

Τετάρτη 21 Δεκεμβρίου 2016

Alanine-scanning mutagenesis of human signal transducer and activator of transcription 1 to estimate loss- or gain-of-function variants

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Publication date: Available online 20 December 2016
Source:Journal of Allergy and Clinical Immunology
Author(s): Reiko Kagawa, Ryoji Fujiki, Miyuki Tsumura, Sonoko Sakata, Shiho Nishimura, Yuval Itan, Xiao-Fei Kong, Zenichiro Kato, Hidenori Ohnishi, Osamu Hirata, Satoshi Saito, Maiko Ikeda, Jamila El Baghdadi, Aziz Bousfiha, Kaori Fujiwara, Matias Oleastro, Judith Yancoski, Laura Perez, Silvia Danielian, Fatima Ailal, Hidetoshi Takada, Toshiro Hara, Anne Puel, Stéphanie Boisson-Dupuis, Jacinta Bustamante, Jean-Laurent Casanova, Osamu Ohara, Satoshi Okada, Masao Kobayashi
BackgroundGermline heterozygous mutations in human signal transducer and activator of transcription 1 (STAT1) can cause loss of function (LOF), as in patients with Mendelian susceptibility to mycobacterial diseases, or gain of function (GOF), as in patients with chronic mucocutaneous candidiasis. LOF and GOF mutations are equally rare and can affect the same domains of STAT1, especially the coiled-coil domain (CCD) and DNA-binding domain (DBD). Moreover, 6% of patients with chronic mucocutaneous candidiasis with a GOF STAT1 mutation have mycobacterial disease, obscuring the functional significance of the identified STAT1 mutations. Current computational approaches, such as combined annotation-dependent depletion, do not distinguish LOF and GOF variants.ObjectiveWe estimated variations in the CCD/DBD of STAT1.MethodsWe mutagenized 342 individual wild-type amino acids in the CCD/DBD (45.6% of full-length STAT1) to alanine and tested the mutants for STAT1 transcriptional activity.ResultsOf these 342 mutants, 201 were neutral, 30 were LOF, and 111 were GOF mutations in a luciferase assay. This assay system correctly estimated all previously reported LOF mutations (100%) and slightly fewer GOF mutations (78.1%) in the CCD/DBD of STAT1. We found that GOF alanine mutants occurred at the interface of the antiparallel STAT1 dimer, suggesting that they destabilize this dimer. This assay also precisely predicted the effect of 2 hypomorphic and dominant negative mutations, E157K and G250E, in the CCD of STAT1 that we found in 2 unrelated patients with Mendelian susceptibility to mycobacterial diseases.ConclusionThe systematic alanine-scanning assay is a useful tool to estimate the GOF or LOF status and the effect of heterozygous missense mutations in STAT1 identified in patients with severe infectious diseases, including mycobacterial and fungal diseases.



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