Sandbox GGC9: Difference between revisions

RAG1 and RAG2 together form the RAG Complex (RAG Recombinases), which are responsible for regulating the DNA cleavage phase during V(D)J recombination. V(D)J recombination functions to produce a plethora of immune molecules in developing B and T immune cells. The B and T cells contain proteins on their surfaces which allow for the recognition of different pathogens affecting the body and may illicit immune responses. The genes which are responsible for making these proteins have different segments which are V, variable, D, diversity and J, joining. These segments can be combined and rearranged to create the diversity required for the proteins for the B and T cells.  RAG1 functions as the catalytic portion while RAG2, although not catalytic, is required for RAG1 to function.[1] RAG1 controls the ability of the DNA to bind to the RSS or recombination signal sequences. This is achieved by the ability of the RAG1 to create a double-stranded break between the (RSS) and the adjacent coding sequence. This rearrangement is carried out in the following way: introduction of a nick in the DNA backbone through hairpin formation and then creating a hydroxyl group at the 3' end which attacks the phosphodiester bond on the opposite strand.[1] This mechanism is a direct transesterification reaction which results in four individual DNA ends. Histones also assist in the nicking and hairpinning of the strands. The result is the recombination of variable genes joining to produce proteins in a response to different pathogens.[1] Additionally to the role played in V(D)J, RAG also assists B cell allelic exclusion. This means that it is able to silence one allele of the B cell but can silence the other allele. RAG1 also possess ubiquitin properties. Newer Studies suggest that the RAG1/2 recombinase complex acts as a transposon, with similar mechanisms.[2]