Fanconi anemia group D2 protein is a protein that in humans is encoded by the FANCD2 gene. [4] [5] The Fanconi anemia complementation group (FANC) currently includes FANCA, FANCB, FANCC, FANCD1 (also called BRCA2), FANCD2 (this gene), FANCE, FANCF, FANCG, FANCI , FANCJ, FANCL, FANCM, FANCN and FANCO.
Fanconi anemia is a disorder with a recessive Mendelian pattern of inheritance characterized by chromosomal instability, hypersensitivity to DNA crosslinking agents, increased chromosomal breakage, and defective DNA repair. The members of the Fanconi anemia complementation group do not share sequence similarity; they are related by their assembly into a common nuclear protein complex. This gene encodes the protein for complementation group D2. This protein is monoubiquitinated in response to DNA damage, resulting in its localization to nuclear foci with other proteins (BRCA1 and BRCA2) involved in homology-directed DNA repair (see Figure: Recombinational repair of DNA double-strand damages). A nuclear complex containing FANCA, [Fanconi anemia, complementation group A], FANCB, FANCC, FANCE, FANCF, FANCL and FANCG proteins is required for the activation of the FANCD2 protein to the mono-ubiquitinated isoform. [13]
Mono-ubiquination of FANCD2 is essential for repairing DNA interstrand crosslinks, and clamps the protein on DNA together with its partner protein FANCI. The monoubiquitinated FANCD2:FANCI complex coats DNA in a filament-like array, potentially as a way to protect DNA associated with stalled replication. [14]
Mono-ubiquitination is also required for interaction with the nuclease FAN1. FAN1 recruitment and its consequent activity restrain DNA replication fork progression and prevent chromosome abnormalities from occurring when DNA replication forks stall. [15]
Humans with a FANCD deficiency display hypogonadism, male infertility, impaired spermatogenesis, and reduced female fertility. Similarly, mice deficient in FANCD2 show hypogonadism, impaired fertility and impaired gametogenesis. [16]
In the non-mutant mouse, FANCD2 is expressed in spermatogonia, pre-leptotene spermatocytes, and in spermatocytes in the leptotene, zygotene and early pachytene stages of meiosis. [17] In synaptonemal complexes of meiotic chromosomes, activated FANCD2 protein co-localizes with BRCA1 (breast cancer susceptibility protein). [13] FANCD2 mutant mice exhibit chromosome mis-pairing during the pachytene stage of meiosis and germ cell loss. [18] Activated FANCD2 protein may normally function prior to the initiation of meiotic recombination, perhaps to prepare chromosomes for synapsis, or to regulate subsequent recombination events. [13]
Tobacco smoke suppresses the expression of FANCD2, which codes for a DNA damage "caretaker" or repair mechanism. [19]
FANCD2 mutant mice have a significantly increased incidence of tumors including ovarian, gastric and hepatic adenomas as well as hepatocellular, lung, ovarian and mammary carcinomas. [16] [18] Humans with a FANCD2 deficiency have increased acute myeloid leukemia, and squamous cell carcinomas (head and neck squamous cell carcinomas and anogenital carcinomas). [16] Lung squamous tumors express high levels of FANCD2 and members of Fanconia anemia pathway. [20]
FANCD2 monoubiquitination is also a potential therapeutic target in the treatment of cancer. [21]
FANCD2 has been shown to interact with:
Breast cancer type 1 susceptibility protein is a protein that in humans is encoded by the BRCA1 gene. Orthologs are common in other vertebrate species, whereas invertebrate genomes may encode a more distantly related gene. BRCA1 is a human tumor suppressor gene and is responsible for repairing DNA.
Fanconi anemia (FA) is a rare, AR, genetic disease resulting in impaired response to DNA damage in the FA/BRCA pathway. Although it is a very rare disorder, study of this and other bone marrow failure syndromes has improved scientific understanding of the mechanisms of normal bone marrow function and development of cancer. Among those affected, the majority develop cancer, most often acute myelogenous leukemia (AML), MDS, and liver tumors. 90% develop aplastic anemia by age 40. About 60–75% have congenital defects, commonly short stature, abnormalities of the skin, arms, head, eyes, kidneys, and ears, and developmental disabilities. Around 75% have some form of endocrine problem, with varying degrees of severity. 60% of FA is FANC-A, 16q24.3, which has later onset bone marrow failure.
DNA repair protein RAD51 homolog 1 is a protein encoded by the gene RAD51. The enzyme encoded by this gene is a member of the RAD51 protein family which assists in repair of DNA double strand breaks. RAD51 family members are homologous to the bacterial RecA, Archaeal RadA and yeast Rad51. The protein is highly conserved in most eukaryotes, from yeast to humans.
Fanconi anemia group C protein is a protein that in humans is encoded by the FANCC gene. This protein delays the onset of apoptosis and promotes homologous recombination repair of damaged DNA. Mutations in this gene result in Fanconi anemia, a human rare disorder characterized by cancer susceptibility and cellular sensitivity to DNA crosslinks and other damages.
Fanconi anaemia, complementation group A, also known as FAA, FACA and FANCA, is a protein which in humans is encoded by the FANCA gene. It belongs to the Fanconi anaemia complementation group (FANC) family of genes of which 12 complementation groups are currently recognized and is hypothesised to operate as a post-replication repair or a cell cycle checkpoint. FANCA proteins are involved in inter-strand DNA cross-link repair and in the maintenance of normal chromosome stability that regulates the differentiation of haematopoietic stem cells into mature blood cells.
Fanconi anemia group G protein is a protein that in humans is encoded by the FANCG gene.
DNA repair protein XRCC2 is a protein that in humans is encoded by the XRCC2 gene.
Fanconi anemia group J protein is a protein that in humans is encoded by the BRCA1-interacting protein 1 (BRIP1) gene.
Fanconi anemia group F protein is a protein that in humans is encoded by the FANCF gene.
Fanconi anemia, complementation group E protein is a protein that in humans is encoded by the FANCE gene. The Fanconi anemia complementation group (FANC) currently includes FANCA, FANCB, FANCC, FANCD1, FANCD2, FANCE, FANCF, FANCG, and FANCL. Fanconi anemia is a genetically heterogeneous recessive disorder characterized by cytogenetic instability, hypersensitivity to DNA cross-linking agents, increased chromosomal breakage, and defective DNA repair. The members of the Fanconi anemia complementation group do not share sequence similarity; they are related by their assembly into a common nuclear protein complex. This gene encodes the protein for complementation groufcrp E.
E3 ubiquitin-protein ligase FANCL is an enzyme that in humans is encoded by the FANCL gene.
Fanconi anemia group B protein is a protein that in humans is encoded by the FANCB gene.
Fanconi anemia, complementation group I (FANCI) also known as KIAA1794, is a protein which in humans is encoded by the FANCI gene. Mutations in the FANCI gene are known to cause Fanconi anemia.
Partner and localizer of BRCA2, also known as PALB2 or FANCN, is a protein which in humans is encoded by the PALB2 gene.
Fanconi anemia, complementation group M, also known as FANCM is a human gene. It is an emerging target in cancer therapy, in particular cancers with specific genetic deficiencies.
FANC proteins are a network of at least 15 proteins that are associated with a cell process known as the Fanconi anemia.
Alan D. D'Andrea is an American cancer researcher and the Fuller American Cancer Society Professor of Radiation Oncology at Harvard Medical School. D'Andrea's research at the Dana Farber Cancer Institute focuses on chromosome instability and cancer susceptibility. He is currently the director of the Center for DNA Damage and Repair and the director of the Susan F. Smith Center for Women's Cancer.
A hereditary cancer syndrome is a genetic disorder in which inherited genetic mutations in one or more genes predispose the affected individuals to the development of cancer and may also cause early onset of these cancers. Hereditary cancer syndromes often show not only a high lifetime risk of developing cancer, but also the development of multiple independent primary tumors.
FANCD2/FANCI-associated nuclease 1 (KIAA1018) is an enzyme that in humans is encoded by the FAN1 gene. It is a structure dependent endonuclease. It is thought to play an important role in the Fanconi Anemia (FA) pathway.
A double-strand break repair model refers to the various models of pathways that cells undertake to repair double strand-breaks (DSB). DSB repair is an important cellular process, as the accumulation of unrepaired DSB could lead to chromosomal rearrangements, tumorigenesis or even cell death. In human cells, there are two main DSB repair mechanisms: Homologous recombination (HR) and non-homologous end joining (NHEJ). HR relies on undamaged template DNA as reference to repair the DSB, resulting in the restoration of the original sequence. NHEJ modifies and ligates the damaged ends regardless of homology. In terms of DSB repair pathway choice, most mammalian cells appear to favor NHEJ rather than HR. This is because the employment of HR may lead to gene deletion or amplification in cells which contains repetitive sequences. In terms of repair models in the cell cycle, HR is only possible during the S and G2 phases, while NHEJ can occur throughout whole process. These repair pathways are all regulated by the overarching DNA damage response mechanism. Besides HR and NHEJ, there are also other repair models which exists in cells. Some are categorized under HR, such as synthesis-dependent strain annealing, break-induced replication, and single-strand annealing; while others are an entirely alternate repair model, namely, the pathway microhomology-mediated end joining (MMEJ).
| Excision repair | |
|---|---|
| Other forms of repair | |
| Other/ungrouped proteins | |
| Regulation | |
| Other/ungrouped | |
