Rapid capillary zone electrophoresis in isoelectric histidine buffer: High resolution of the poly-T tract allelic variants in intron 8 of the CFTR gene

Abstract

The poly-T tract in intron 8 of the Cystic fibrosis conductance transmembrane regulator (CFTR) gene exists in three variants, ST, 7T, and 9T. The 7T and 9T variants generate a predominantly normal transcript, whereas the 5T variant engenders an anomalous product. The analysis of the poly-T tract is assuming increasing relevance, both to assess the implication of the CFTR gene in congenital bilateral absence of the vas deferens and to evaluate genotype-phenotype correlation in cystic fibrosis. Mapping of the poly-T tract has been performed by cumbersome and time-consuming methodologies. Capillary zone electrophoresis, combined with laser-induced fluorescence detection, was introduced for a rapid separation of the poly-T tract amplified products. As separation buffer, we adopted 200 mmol/L histidine (pH = pI = 7.6), and the capillary was filled with 10% polyacrylamide, allowing separations in less than 10 min. Capillary zone electrophoresis results were in perfect agreement with dot-blot analysis.