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DNA Rearrangements. Homologous recombination results in the reassortment of genes between chromosome pairs without altering the arrangement of genes within the genome. In contrast, other types of recombinational events lead to rearrangements of genomic DNA. Some of these DNA rearrangements are important in controlling gene expression in ...
- Geoffrey M Cooper
- 2000
1 RearrangementReactions. 1. Rearrangement ReactionsA rearrangement reaction is a board class of organic reactions in which an atom, ion, group of atoms, or chemical unit migrates from one atom to another atom in the same or different species, resulting in a structural isomer o.
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Dec 30, 2022 · (A) rearrangement of α chain and (B) β chain (C) protein structure of TCR. The enzyme that produces this diversity is a complex called the V(D)J recombinase. The recombination occurs in two parts: first double-stranded breaks are made at re- combination signal sequence (RSS) sites, then the breaks are repaired by the general double-stranded break repair mechanism.
The Baeyer-Villager Oxidation/Rearrangement O O O O RH O O R1 R2 O R1 R2 O OO O R Criegee intermediate O R1O R2+ O OR Alkyl group that migrates does so with retention of configuration More electron-rich (most substituted) alkyl group migrates in preference Mechanism: RO3H For a review, see: M. Renz, B. Meunier, Eur. J. Org. Chem. 1999, 737.
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- Specimen Types
- Antibody-Based Clonality Testing
- Nucleic Acid–Based Testing
- Southern Blot Hybridization
- Polymerase Chain Reaction
- Detection Systems
- Interpretative Guidelines
There are a number of clinical specimens collected for routine diagnostic assessment of leukemias and lymphomasFresh and frozen tissue is a preferred specimen for clonality analysisBone marrow aspirate – ACD, heparin, and EDTA are all acceptable anticoagulantsPeripheral blood – ACD, heparin, and EDTA are all acceptable anticoagulantsPrinciple: Labeled monoclonal antibodies (MoAb) targeting Ig or TCR proteins on the cell surface are used to identify monoclonal lymphoid populations by flow cytometry or multiparameter flow cytometryLabeled MoAb-targeting cell surface immunoglobulin kappa and lambda light chains can identify clonality in suspected B cell lymphoproliferations. The ratio of kappa/lambda light chain in peripheral...Panels of monoclonal antibodies targeting a variety of variable region TCR beta chains can identify clonality in suspected T cell lymphoproliferations, as disproportionate representation of Vβ usag...Immunophenotyping studies are done first to establish lineageNucleic acid–based clonality tests can provide critical data necessary to discriminate between malignant and reactive lymphoproliferative processes cases where morphology, flow cytometric, and immu...Since leukemias and lymphomas all arise from a single malignantly transformed lymphoid cell, all leukemias and lymphomas should carry unique clonal rearrangements of one or more antigen receptor ge...In B cell malignancies clonal rearrangements should include the immunoglobulin heavy and/or light chain genes and in T cell malignancies clonal rearrangements of the TCR genesIn practice, there are inefficiencies, which reduce detection rates, as well as rearrangements that are not determinative of B cell or T cell lineage (e.g., clonal TCR rearrangements are often pres...Principle: Gene rearrangements within the antigen receptor genes add, delete, or alter restriction enzyme sites, which change the size of the DNA fragments. Changes to the germline pattern can be i...AdvantagesDisadvantagesFirst described by Dr. Alexander Morley in 1990 (Trainor et al. 1990) as an improvement over Southern blot hybridization techniquesPCR-based clonality assays are now routinely used to assist in differentiating between malignant and reactive processes in suspect lymphoproliferationsPCR has replaced Southern blot hybridization assays as the “gold standard” for clonality assessmentWhen used consistent with the appropriate guidelines and with a proven diagnostic testing strategy these standardized assays can identify clonality in approximately 99% of all B cell malignancies a...Heteroduplex analysisHeteroduplex protocolCapillary electrophoresis detects fluorescently labeled amplicon productsDenaturing gradient gel electrophoresis (DGGE)Interpretative guidelines for clonality tests are assay- and specimen-specificMost investigators do not support interpretation using purely objective criteriaThe following approaches have been proposed for TCRG assaysTroubleshooting PCR-based clonality resultsThe DNA rearrangements are caused by a set of mechanisms that are collectively called genetic recombination. Two broad classes are commonly recognized—general recombination and site-specific recombination. In this part of the chapter we discuss the first of these two mechanisms; in the next part, we consider the second mechanism.
People also ask
What is a rearrangement reaction?
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What is a 1 2 rearrangement?
Rearrangement Reactions A rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule. 1, 2-Rearrangements A 1, 2-rearrangement is an organic reaction where a substituent moves from one atom to another atom in a chemical compound.
