SLX4 (also known as BTBD12 and FANCP) is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

involved in

DNA repair DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA da ...

, where it has important roles in the final steps of

homologous recombination Homologous recombination is a type of genetic recombination in which genetic information is exchanged between two similar or identical molecules of double-stranded or single-stranded nucleic acids (usually DNA as in cellular organisms but may ...

. Mutations in the gene are associated with the disease

Fanconi anemia Fanconi anaemia (FA) is a rare genetic disease resulting in impaired response to DNA damage. Although it is a very rare disorder, study of this and other bone marrow failure syndromes has improved scientific understanding of the mechanisms of no ...

. The version of SLX4 present in humans and other mammals acts as a sort of scaffold upon which other proteins form several different multiprotein complexes. The SLX1-SLX4 complex acts as a Holliday junction resolvase. As such, the complex cleaves the links between two homologous chromosomes that form during homologous recombination. This allows the two linked chromosomes to resolve into two unconnected double-strand DNA molecules. The SLX4 interacting protein interacts with SLX4 in the DNA repair process, specifically in interstrand crosslink repair. SLX4 also associates with RAD1,

RAD10 RAD1 can refer to: * Nintendo Research & Development 1 commonly abbreviated as Nintendo R&D1, was Nintendo's oldest video game development team. It was known as before splitting in 1978. Its creation coincided with Nintendo's entry into the v ...

and SAW1 in the single-strand annealing pathway of homologous recombination. The DNA repair function of SLX4 is involved in sensitivity to proton beam radiation.

Model organisms

Model organisms have been prominent in the study of SLX4 function. It was identified in 2001 during a screen for lethal mutations in

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constit ...

cells lacking a functional copy of the

Sgs1 Sgs1, also known as slow growth suppressor 1, is a DNA helicase protein found in ''Saccharomyces cerevisiae''. It is a homolog of the bacterial RecQ helicase. Like the other members of the RecQ helicase family, Sgs1 is important for DNA repair ...

protein. Based on that, SLX4 was grouped with several other proteins produced by SLX (''s''ynthetic ''l''ethal of unknown function) genes. A conditional

knockout mouse A knockout mouse, or knock-out mouse, is a genetically modified mouse (''Mus musculus'') in which researchers have inactivated, or " knocked out", an existing gene by replacing it or disrupting it with an artificial piece of DNA. They are importa ...

line, called ''Slx4^{tm1a(EUCOMM)Wtsi}'' was generated as part of the International Knockout Mouse Consortium program, a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists. Male and female animals underwent a standardized

phenotypic screen In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...

to determine the effects of deletion. Twenty four tests were carried out on

mutant In biology, and especially in genetics, a mutant is an organism or a new genetic character arising or resulting from an instance of mutation, which is generally an alteration of the DNA sequence of the genome or chromosome of an organism. It ...

mice and ten significant abnormalities were observed. A viability at weaning study found less

homozygous Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mo ...

animals were present than predicted by

Mendelian ratio Mendelian inheritance (also known as Mendelism) is a type of biological inheritance following the principles originally proposed by Gregor Mendel in 1865 and 1866, re-discovered in 1900 by Hugo de Vries and Carl Correns, and later popularized ...

. Homozygous mutant animals of both sexes were sub-fertile and homozygous females had a reduced body weight, body length, heart weight,

platelet Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby i ...

count and lean mass. Homozygotes of both sex had abnormal eye sizes, narrow eye openings, skeletal defects (including scoliosis and fusion of vertebrae), and displayed an increase in DNA instability as shown by a micronucleus test. This and further analysis revealed the mouse phenotype to model the human genetic illness, Fanconi anemia. The association was confirmed when patients with the disease were found to have mutations in their SLX4 gene.

References

{{reflist, 2 DNA repair Genes mutated in mice