PathwayStep2909 Translesion synthesis by DNA polymerases bypassing lesion on DNA template DNA Damage Bypass Authored: Gopinathrao, G, 2004-02-02 17:30:34 In addition to various processes for removing damaging lesions from the DNA, cells have developed specific mechanisms for tolerating unexcised damages during the replication of the genome. Such processes are collectively called DNA damage bypass pathways. Several proteins including novel Y-family polymerases that have been recently identified in multitude of organisms are involved in this process.<BR> Translesion synthesis (TLS) or replicative bypass of damaged bases that are known to arrest high fidelity, highly processive polymerases involved in DNA replication is carried out by error-prone polymerases Pol zeta, Pol eta and Rev3 protein among others. TLS is implicated in UV and chemical induced mutagenesis of normal human cells where lesions in the replicating genome are carried over to the newly formed daughter cells.<BR> All these 3 enzymes are found to lack 3’->5’ exonuclease activity, while exhibiting low fidelity, weak processivity and sufficient polymerase activities. An outline of the bypass synthesis by these 3 enzymes is annotated here. Complete details of damage recognition and discrimination, initiation of specific polymerase activity and the finer mechanisms are yet to be elucidated. Pubmed10925197 Pubmed11595180 Pubmed12800216 Reactome Database ID Release 4373893 Reactome, http://www.reactome.org ReactomeREACT_2174