Significant Role of Segmental Duplications and SIDD Sites in Chromosomal Translocations of Hematological Malignancies: A Multi-parametric Bioinformatic Analysis

Recurrent non-random chromosomal translocations are hallmark characteristics of leukemogenesis, and however, molecular mechanisms underlying these rearrangements are less explored. The fundamental question is, why and how chromosomes break and reunite so precisely in the genome. Meticulous understanding of mechanism leading to chromosomal rearrangement can be achieved by characterizing breakpoints. To address this hypothesis, a novel multi-parametric computational approach for characterization of major leukemic translocations within and around breakpoint region was performed. To best of our knowledge, this bioinformatic analysis is unique in finding the presence of segmental duplications (SDs) flanking breakpoints of all major leukemic translocation. Breakpoint islands (BpIs) were analyzed for stress-induced duplex destabilization (SIDD) sites along with other complex genomic architecture and physicochemical properties. Our study distinctly emphasizes on the probable correlative role of SDs, SIDD sites and various genomic features in the occurrence of breakpoints. Further, it also highlights potential features which may be playing a crucial role in causing double-strand breaks, leading to translocation.

Identifying RNA recombination events and non-covalent RNA-RNA interactions with the molecular colony technique

Molecular colonies (also known under names nanocolonies, polonies, RNA or DNA colonies, PCR colonies) form when nucleic acids are amplified in a porous solid or semi-solid medium, such as a gel, which contains a system for the exponential multiplication of RNA or DNA. As an individual colony comprises many copies of a single molecule (a molecular clone), the method can be used for the detection, enumeration, and analysis of individual DNA or RNA molecules, including the products of such rare events as RNA recombinations. Here we describe protocols for the detection of RNA molecules by growing colonies of RNA (in a gel containing Qβ replicase, the RNA-dependent RNA polymerase of phage Qβ) or cDNA (in a gel containing the components of PCR), and visualizing them by hybridization with fluorescent probes directly in the gel, including in real time, or by hybridization with fluorescent or radioactive probes followed by transfer to a nylon membrane.