Alternative Splicing at a NAGNAG Acceptor Site as a Novel Phenotype Modifier

Approximately 30% of alleles causing genetic disorders generate premature termination codons (PTCs), which are usually associated with severe phenotypes. However, bypassing the deleterious stop codon can lead to a mild disease outcome. Splicing at NAGNAG tandem splice sites has been reported to result in insertion or deletion (indel) of three nucleotides. We identified such a mechanism as the origin of the mild to asymptomatic phenotype observed in cystic fibrosis patients homozygous for the E831X mutation (2623G>T) in the CFTR gene. Analyses performed on nasal epithelial cell mRNA detected three distinct isoforms, a considerably more complex situation than expected for a single nucleotide substitution. Structure-function studies and in silico analyses provided the first experimental evidence of an indel of a stop codon by alternative splicing at a NAGNAG acceptor site. In addition to contributing to proteome plasticity, alternative splicing at a NAGNAG tandem site can thus remove a disease-causing UAG stop codon. This molecular study reveals a naturally occurring mechanism where the effect of either modifier genes or epigenetic factors could be suspected. This finding is of importance for genetic counseling as well as for deciding appropriate therapeutic strategies

Proteomic analysis for the study of amniotic fluid protein composition.

Abstract Amniotic fluid (AF), routinely used for prenatal diagnosis, contains large amounts of proteins produced by the amnion epithelial cells, fetal tissues, fetal excretions and placental tissuesAlthough many amniotic fluid proteins have been identified and are currently used to detect potential fetal anomalies, little is known about the functions of these proteins and how they interact with one another. Identification of changes in the protein content of amniotic fluid, therefore, may be used to detect a particular type of pathology, or to ascertain a specific genetic disorder. In the present work we used a proteomic approach, combining 2DE and MS, in order to study the protein composition of AFS

Tradition and modernity in the mediterranean cities. The tunisian cities: Tunis, Kairouan, Tozeur, Nefta.

L’articolo fa un confronto tra le differenti forme urbane delle città del Nord Africa, in particolare quelle della Tunisia (Tunisi, Kairouan, Tozeur, Nefta). Tali città, distribuite tra il Nord ed il Sud del paese, esprimono, nelle loro medine, l’identità della forma urbana e ne dichiarano la modernità lungo i loro bordi. Tunisi, posta tra due laghi, costruisce la sua modernità con la città coloniale che, anche se con linguaggi diversi, evidenzia i temi del Mediterraneo. La città di Kairouan mantiene la sua identità nella grande moschea, luogo centrale di organizzazione urbana. Le città d’oasi, come Tozeur e Nefta, esprimono il loro rapporto col paesaggio ed evidenziano con le loro architetture i materiali usati

Abstracts from the 23rd Italian congress of Cystic Fibrosis and the 13th National congress of Cystic Fibrosis Italian Society

Cystic Fibrosis (CF) occurs most frequently in caucasian populations. Although less common, this disorder have been reported in all the ethnicities. Currently, there are more than 2000 described sequence variations in CFTR gene, uniformly distributed and including variants pathogenic and benign (CFTR1:www.genet.sickkids.on.ca/). To date,only a subset have been firmily established as variants annotated as disease-causing (CFTR2: www.cftr2.org). The spectrum and the frequency of individual CFTR variants, however, vary among specific ethnic groups and geographic areas. Genetic screening for CF with standard panels of CFTR mutations is widely used for the diagnosis of CF in newborns and symptomatic patients, and to diagnose CF carrier status. These screening panels have an high diagnostic sensitivity (around 85%) for CFTR mutations in caucasians populations but very low for non caucasians. Developed in the last decade, Next-Generation Sequencing (NGS) has been the last breakthrough technology in genetic studies with a substantial reduction in cost per sequenced base and a considerable enhancement of the sequence generation capabilities. Extended CFTR gene sequencing in NGS includes all the coding regions, the splicing sites and their flankig intronic regions, deep intronic regions where are localized known mutations,the promoter and the 5'-3' UTR regions. NGS allows the analysis of many samples concurrently in a shorter period of time compared to Sanger method . Moreover, NGS platforms are able to identify CFTR copy number variation (CNVs), not detected by Sanger sequencing. This technology has provided new and reliable approaches to molecular diagnosis of CF and CFTR-Related Disorders. It also allows to improve the diagnostic sensitivity of newborn and carrier screeningmolecular tests. In fact, bioinformatics tools suitable for all the NGS platforms can filter data generated from the gene sequencing, and analyze only mutations with well-established disease liability. This approach allows the development of targeted mutations panels with a higher number of frequent CF mutations for the target populationcompared to the standard panels and a consequent enhancement of the diagnostic sensitivity. Moreover, in the emerging challenge of diagnosing CF in non caucasians patients, the possibility of customize a NGS targeted mutations panel should increase the diagnostic sensitivity when the target population has different ethnicities