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.
Viral infectivity factor, or Vif, is an accessory protein found in HIV and other lentiviruses. Its role is to disrupt the antiviral activity of the human enzyme APOBEC by targeting it for ubiquitination and cellular degradation. APOBEC is a cytidine deaminase enzyme that mutates viral nucleic acids.
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.
The retroviral psi packaging element, also known as the Ψ RNA packaging signal, is a cis-acting RNA element identified in the genomes of the retroviruses Human immunodeficiency virus (HIV) and Simian immunodeficiency virus (SIV). It is involved in regulating the essential process of packaging the retroviral RNA genome into the viral capsid during replication. The final virion contains a dimer of two identical unspliced copies of the viral genome.
DNA-directed RNA polymerase II subunit RPB2 is an enzyme that in humans is encoded by the POLR2B gene.
DNA-directed RNA polymerase II subunit RPB9 is an enzyme that in humans is encoded by the POLR2I gene.
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.
AP-1 complex subunit gamma-like 2 is a protein that in humans is encoded by the AP1G2 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.
Protein arginine N-methyltransferase 6 is an enzyme that in humans is encoded by the PRMT6 gene.
Probable DNA dC->dU-editing enzyme APOBEC-3D is a protein that in humans is encoded by the APOBEC3D gene.
GBA2 is the gene that encodes the enzyme non-lysosomal glucosylceramidase in humans. It has glucosylceramidase activity.
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.
Somatic hypermutation is a cellular mechanism by which the immune system adapts to the new foreign elements that confront it, as seen during class switching. A major component of the process of affinity maturation, SHM diversifies B cell receptors used to recognize foreign elements (antigens) and allows the immune system to adapt its response to new threats during the lifetime of an organism. Somatic hypermutation involves a programmed process of mutation affecting the variable regions of immunoglobulin genes. Unlike germline mutation, SHM affects only an organism's individual immune cells, and the mutations are not transmitted to the organism's offspring. Because this mechanism is merely selective and not precisely targeted, somatic hypermutation has been strongly implicated in the development of B-cell lymphomas and many other cancers.
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.
Human APOBEC3F is another host factor that blocks human immunodeficiency virus type 1 replication. Zheng YH, Irwin D, Kurosu T, Tokunaga K, Sata T, Peterlin BM. J Virol. 2004 Jun;78(11):6073-6. doi: 10.1128/JVI.78.11.6073-6076.2004.
