RecQ-mediated genome instability protein 1 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 ''RMI1''
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 ...
.
Genetic disorders
Mutations in RMI1 are associated with
Bloom-Syndrome like disorder. Two patients, both with
microcephalic dwarfism came from the same family. They carried identical heterozygous mutations:
255_1259delLys419LeufsTer5].
Function
RMI1 protein is a component of the Bloom Syndrome Complex. RMI1 protein is made up of 2 OB (oligonucleotide binding) domains. OB1 binds to
TOP3A, Topoisomerase III alpha,
while OB2 binds to RMI2 within the Bloom Syndrome complex, and
FANCM
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.
Function
The protein encoded by this gene, FANCM displays DNA bi ...
of the Fanconi Anaemia pathway.
An insert within OB1 domain of RMI1 inserts into the catalytic centre of Topoisomerase III alpha, and is necessary for the optimal activity of this enzyme during cellular DNA repair and homologous recombination.
Meiosis
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 budding 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 ...
'',
TOP3 (a
type I topoisomerase
In molecular biology Type I topoisomerases are enzymes that cut one of the two strands of double-stranded DNA, relax the strand, and reanneal the strand. They are further subdivided into two structurally and mechanistically distinct topoisomerase ...
) and its accessory factor RMI1 form a
heterodimer
In biochemistry, a protein dimer is a macromolecular complex formed by two protein monomers, or single proteins, which are usually non-covalently bound. Many macromolecules, such as proteins or nucleic acids, form dimers. The word ''dimer'' has ...
that functions to allow passage of one DNA single strand through another. The TOP3-RMI1 heterodimer associates with
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 ...
(
Bloom helicase ortholog
Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a spec ...
) to form a complex that catalyzes dissolution of double
Holliday junction
A Holliday junction is a branched nucleic acid structure that contains four double-stranded arms joined. These arms may adopt one of several conformations depending on buffer salt concentrations and the sequence of nucleobases closest to the ju ...
s.
Furthermore, the TOP3-RMI1 heterodimer participates in all meiotic recombination functions associated with
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 ...
, most significantly as an early recombination intermediate chaperone, promoting regulated
crossover
Crossover may refer to:
Entertainment
Albums and songs
* ''Cross Over'' (Dan Peek album)
* ''Crossover'' (Dirty Rotten Imbeciles album), 1987
* ''Crossover'' (Intrigue album)
* ''Crossover'' (Hitomi Shimatani album)
* ''Crossover'' (Yoshino ...
and
non-crossover recombination and preventing accumulation of aberrant recombination intermediates.
In particular, the TOP3-RMI1–SGS1 complex promotes early formation of non-crossover recombinants during meiosis.
References
Further reading
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