Post-transcriptional control of candidate risk genes for type 1 diabetes by rare genetic variants

The genetic variation causal for predisposition to type 1 diabetes (T1D) remains unidentified for the majority of known T1D risk loci. MicroRNAs function as post-transcriptional gene regulators by targeting microRNA-binding sites in the 3' untranslated regions (UTR) of mRNA. Genetic variation within the 3'-UTR of T1D-associated genes may contribute to T1D development by altering microRNA-mediated gene regulation. In silico analysis of variable sites predicted altered microRNA binding in established T1D loci. Functional implications were assessed for variable sites in the 3'-UTR of T1D candidate risk genes CTLA4 and IL10, both involved in immune regulation. We confirmed that in these genes 3'-UTR variation either disrupted or introduced a microRNA-binding site, affecting the repressive capacity of miR-302a* and miR-523, respectively. Our study points to the potential of 3'-UTR variation to affect T1D pathogenesis by altering post-transcriptional gene regulation by microRNAs.Transplantation and autoimmunit

Dynamic assembly of end-joining complexes requires interaction between Ku70/80 and XRCC4

DNA double-strand break (DSB) repair by nonhomologous end joining (NHEJ) requires the assembly of several proteins on DNA ends. Although biochemical studies have elucidated several aspects of the NHEJ reaction mechanism, much less is known about NHEJ in living cells, mainly because of the inability to visualize NHEJ repair proteins at DNA damage. Here we provide evidence that a pulsed near IR laser can produce DSBs without any visible alterations in the nucleus, and we show that NHEJ proteins accumulate in the irradiated areas. The levels of DSBs and Ku accumulation diminished in time, showing that this approach allows us to study DNA repair kinetics in vivo. Remarkably, the Ku heterodimers on DNA ends w

RNA Interference: Its Use as Antiviral Therapy

RNA interference (RNAi) is a sequence-specific gene-silencing mechanism that has been proposed to function as a defence mechanism of eukaryotic cells against viruses and transposons. RNAi was first observed in plants in the form of a mysterious immune response to viral pathogens. But RNAi is more than just a response to exogenous genetic material. Small RNAs termed microRNA (miRNA) regulate cellular gene expression programs to control diverse steps in cell development and physiology. The discovery that exogenously delivered short interfering RNA (siRNA) can trigger RNAi in mammalian cells has made it into a powerful technique for generating genetic knock-outs. It also raises the possibility to use RNAi technology as a therapeutic tool against pathogenic viruses. Indeed, inhibition of virus replication has been reported for several human pathogens including human immunodeficiency virus, the hepatitis B and C viruses and influenza virus. We reviewed the field of antiviral RNAi research in 2003 (Haasnoot et al. 2003), but many new studies have recently been published. In this review, we present a complete listing of all antiviral strategies published up to and including December 2004. The latest developments in the RNAi field and their antiviral application are describe