Structural maintenance of chromosomes protein 6 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, respo ...
that in humans is encoded by the ''SMC6''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
Structure
The SMC6 was discovered first in fission yeast as RAD18 (SMC6). It forms a heterodimeric complex with Spr18 (SMC5) protein. In yeast, SMC5/6 complex has sub-units which consists of SMC5, SMC6 and six nonstructural maintenance of chromosomes (NSE) proteins. Nse1-Nse3-Nse4 subunits bridge the Smc5 head Smc6 and allow the binding of DNA.
It is involved in the
Alternative lengthening of telomeres cancer mechanism.
Role in recombination and meiosis
Smc6 and
Smc5
Structural maintenance of chromosomes protein 5 is a protein encoded by the ''SMC5'' gene in human.
The structural maintenance of chromosomes' complex underlying mechanisms involved in the dynamics of chromatin dynamics is unknown, and new discove ...
proteins form a heterodimeric ring-like structure and together with other non-SMC elements form the SMC-5/6 complex. In the worm ''
Caenorhabditis elegans
''Caenorhabditis elegans'' () is a free-living transparent nematode about 1 mm in length that lives in temperate soil environments. It is the type species of its genus. The name is a blend of the Greek ''caeno-'' (recent), ''rhabditis'' (ro ...
'' this complex interacts with the
HIM-6(BLM) helicase to promote
meiotic recombination
Genetic recombination (also known as genetic reshuffling) is the exchange of genetic material between different organisms which leads to production of offspring with combinations of traits that differ from those found in either parent. In eukaryo ...
intermediate processing and
chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
maturation.
The SMC-5/6 complex in mouse
oocyte
An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female ...
s is essential for the formation of segregation competent bivalents during
meiosis
Meiosis (; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately resu ...
.
In the yeast ''
Saccharomyces cerevisiae
''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungus microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have been o ...
'', SMC6 is necessary for resistance to DNA damage as well as for damage-induced interchromosomal and sister
chromatid
A chromatid (Greek ''khrōmat-'' 'color' + ''-id'') is one half of a duplicated chromosome. Before replication, one chromosome is composed of one DNA molecule. In replication, the DNA molecule is copied, and the two molecules are known as chro ...
recombination.
In humans, a
chromosome breakage syndrome characterized by severe lung disease in early childhood is associated with a
mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
in a component of the SMC-5/6 complex.
Patient’s cells display
chromosome rearrangement
In genetics, a chromosomal rearrangement is a mutation that is a type of chromosome abnormality involving a change in the structure of the native chromosome. Such changes may involve several different classes of events, like Deletion (genetics), de ...
s,
micronuclei
Micronucleus is the name given to the small nucleus that forms whenever a chromosome or a fragment of a chromosome is not incorporated into one of the daughter nuclei during cell division. It usually is a sign of genotoxic events and chromosomal i ...
, sensitivity to
DNA damage
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 ...
and defective
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 ...
.
References
Further reading
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