Somatic hypermutation affects Ig genes during T-dependent B cell responses and is characterized by a high frequency of single base substitutions. Hypermutation is not a completely random process; a study of mutations in different systems has revealed the presence of sequence motifs that target mutation. In a recent analysis of the sequences surrounding individual mutated bases in out-of-frame human IgVH genes, we found that the target motifs around mutated G's and C's are reverse complements of each other. This finding suggests that hypermutation acts on both strands of DNA, which contradicts evidence of a strand-dependent mechanism as suggested by an observed bias in A and T mutations and the involvement of transcriptional machinery. We have now extended our database of out-of-frame genes and determined the sequence motifs flanking mutated A and T nucleotides. In addition, we have analyzed the flanking sequences for different types of nucleotide substitutions separately. Our results confirm the relationship between the motifs for G and C mutations and show that the motifs surrounding mutated A's and T's are weaker and do not have the same relationship. Taken together with our observation of A/T strand bias in out-of-frame genes, this observation suggests that there is a semitargeted G/C mutator that is strand-independent and a separate A/T mutator that is strand-dependent and is less reliant on the local target sequence.
This research output has an Altmetric Attention Score of 6. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 02 May 2017.
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#7,582,553
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Outputs from The Journal of Immunology
#10,433
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#11,947
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Outputs of similar age from The Journal of Immunology
#102
of 287 outputs
Altmetric has tracked 34,365,356 research outputs across all sources so far. This one has received more attention than most of these and is in the 73rd percentile.
So far Altmetric has tracked 35,991 research outputs from this source. They typically receive a little more attention than average, with a mean Attention Score of 6.8. This one has gotten more attention than average, scoring higher than 53% of its peers.
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