C-RAF ELISA Kit

Noonan syndrome (NS) is a genetic condition characterized by congenital heart defects, short stature and characteristic facial features. We here present the case of a girl with moderate learning disabilities, delayed language development, craniofacial features and skin anomalies reminiscent of NS. After a mutation screening of the known NS genes PTPN11, SOS1, RAF1, KRAS, GRB2, BRAF and SHOC2 we found the heterozygous c.755T>C variant in SOS1 causing the p.I252T amino-acid substitution, which was considered possibly pathogenetic by bioinformatic predictions. The same variant was present in the proband's mother, displaying some NS features, and maternal grandfather showing no NS traits, but also by a healthy subject in 1000 genomes project database without phenotype informations. The functional analysis revealed that SOS1 c.755C activated the RAS-ERK intracellular pathway, whereas no effects on RAC-JNK cascade have been detected. After a comparison between the sequence of SOS1 cDNA from peripheral blood and SOS1 genomic DNA, we showed for the first time a differential allelic expression of the SOS1 gene in healthy individuals, thus occurring as a physiologic condition. Interestingly, we found that the mutated allele C was 50% more expressed than the wild-type allele T in all familial carriers. The comparable amount of SOS1 mRNA between mutated individuals and the controls indicates that the variant does not affect SOS1 expression. The present study provides a first evidence of allelic imbalance of SOS1 and pinpoints this condition as a possible mechanism underlying a different penetrance of some SOS1-mutated alleles in unrelated carriers.

Long non-coding RNAs (ncRNAs) are major regulators of gene expression and cell fate. TheINK4locus encodes the tumour suppressor proteins p15(INK4b), p16(INK4a)and p14(ARF)required for cell cycle arrest and whose expression increases during senescence.ANRILis a ncRNA antisense to thep15gene. In proliferative cells,ANRILprevents senescence by repressingINK4genes through the recruitment of Polycomb-group proteins. In models of replicative and RASval12 oncogene-induced senescence (OIS), the expression ofANRILand Polycomb proteins decreases, thus allowingINK4derepression. Here, we found in a model of RAF1 OIS thatANRILexpression rather increases, due in particular to an increased stability. This led us to search for circularANRILisoforms, as circular RNAs are rather stable species. We found that the expression of two circularANRILincreases in several OIS models (RAF1, MEK1 and BRAF). In proliferative cells, they repressp15expression, while in RAF1 OIS, they promote full induction ofp15, p16andp14(ARF)expression. Further analysis of one of these circularANRILshows that it interacts with Polycomb proteins and decreases EZH2 Polycomb protein localization and H3K27me3 at thep15andp16promoters, respectively. We propose that changes in the ratio between Polycomb proteins and circularANRILisoforms allow these isoforms to switch from repressors ofp15gene to activators of allINK4genes in RAF1 OIS. Our data reveal that regulation ofANRILexpression depends on the senescence inducer and underline the importance of circularANRILin the regulation ofINK4gene expression and senescence.