Deamination is the removal of an amino group from a molecule. Enzymes that catalyse this reaction are called deaminases.
Activation-induced cytidine deaminase, also known as AICDA, AID and single-stranded DNA cytosine deaminase, is a 24 kDa enzyme which in humans is encoded by the AICDA gene. It creates mutations in DNA by deamination of cytosine base, which turns it into uracil. In other words, it changes a C:G base pair into a U:G mismatch. The cell's DNA replication machinery recognizes the U as a T, and hence C:G is converted to a T:A base pair. During germinal center development of B lymphocytes, AID also generates other types of mutations, such as C:G to A:T. The mechanism by which these other mutations are created is not well understood. It is a member of the APOBEC family.
RNA editing is a molecular process through which some cells can make discrete changes to specific nucleotide sequences within an RNA molecule after it has been generated by RNA polymerase. It occurs in all living organisms and is one of the most evolutionarily conserved properties of RNAs. RNA editing may include the insertion, deletion, and base substitution of nucleotides within the RNA molecule. RNA editing is relatively rare, with common forms of RNA processing not usually considered as editing. It can affect the activity, localization as well as stability of RNAs, and has been linked with human diseases.
APOBEC3G is a human enzyme encoded by the APOBEC3G gene that belongs to the APOBEC superfamily of proteins. This family of proteins has been suggested to play an important role in innate anti-viral immunity. APOBEC3G belongs to the family of cytidine deaminases that catalyze the deamination of cytidine to uridine in the single stranded DNA substrate. The C-terminal domain of A3G renders catalytic activity, several NMR and crystal structures explain the substrate specificity and catalytic activity.
Missense mRNA is a messenger RNA bearing one or more mutated codons that yield polypeptides with an amino acid sequence different from the wild-type or naturally occurring polypeptide. Missense mRNA molecules are created when template DNA strands or the mRNA strands themselves undergo a missense mutation in which a protein coding sequence is mutated and an altered amino acid sequence is coded for.
The double-stranded RNA-specific adenosine deaminase enzyme family are encoded by the ADAR family genes. ADAR stands for adenosine deaminase acting on RNA. This article focuses on the ADAR proteins; This article details the evolutionary history, structure, function, mechanisms and importance of all proteins within this family.
Apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1 also known as C->U-editing enzyme APOBEC-1 is a protein that in humans is encoded by the APOBEC1 gene.
Cytidine deaminase is an enzyme that in humans is encoded by the CDA gene.
DNA dC->dU-editing enzyme APOBEC-3F is a protein that in humans is encoded by the APOBEC3F gene.
APOBEC1 complementation factor is a protein that in humans is encoded by the A1CF gene.
DNA dC->dU-editing enzyme APOBEC-3C is a protein that in humans is encoded by the APOBEC3C gene.
Probable C->U-editing enzyme APOBEC-2 is a protein that in humans is encoded by the APOBEC2 gene.
Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3A, also known as APOBEC3A, or A3A is a gene of the APOBEC3 family found in humans, non-human primates, and some other mammals. It is a single-domain DNA cytidine deaminase with antiviral effects. While other members of the family such as APOBEC3G are believed to act by editing ssDNA by removing an amino group from cytosine in DNA, introducing a cytosine to uracil change which can ultimately lead to a cytosine to thymine mutation, one study suggests that APOBEC3A can inhibit parvoviruses by another mechanism. The cellular function of APOBEC3A is likely to be the destruction of foreign DNA through extensive deamination of cytosine.Stenglein MD, Burns MB, Li M, Lengyel J, Harris RS. "APOBEC3 proteins mediate the clearance of foreign DNA from human cells". Nature Structural & Molecular Biology. 17 (2): 222–9. doi:10.1038/nsmb.1744. PMC 2921484. PMID 20062055.
Probable DNA dC->dU-editing enzyme APOBEC-3B is a protein that in humans is encoded by the APOBEC3B gene.
Ubiquitin-conjugating enzyme E2 R2 is a protein that in humans is encoded by the UBE2R2 gene.
APOBEC is a family of evolutionarily conserved cytidine deaminases.
DNA dC->dU-editing enzyme APOBEC-3H, also known as Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3H or APOBEC-related protein 10, is a protein that in humans is encoded by the APOBEC3H gene.
C->U-editing enzyme APOBEC-4, also known as Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 4, is a protein that in humans is encoded by the APOBEC4 gene. It is primarily expressed in testis and found in mammals, chicken, but not fishes.
In molecular biology, kataegis describes a pattern of localized hypermutations identified in some cancer genomes, in which a large number of highly patterned basepair mutations occur in a small region of DNA. The mutational clusters are usually several hundred basepairs long, alternating between a long range of C→T substitutional pattern and a long range of G→A substitutional pattern. This suggests that kataegis is carried out on only one of the two template strands of DNA during replication. Compared to other cancer-related mutations, such as chromothripsis, kataegis is more commonly seen; it is not an accumulative process but likely happens during one cycle of replication.
Mutational signatures are characteristic combinations of mutation types arising from specific mutagenesis processes such as DNA replication infidelity, exogenous and endogenous genotoxin exposures, defective DNA repair pathways, and DNA enzymatic editing.
Identification of APOBEC3DE as another antiretroviral factor from the human APOBEC family. Dang Y, Wang X, Esselman WJ, Zheng YH. J Virol. 2006 Nov;80(21):10522-33. doi: 10.1128/JVI.01123-06. Epub 2006 Aug 18.
