KCNQ1 overlapping transcript 1, also known as KCNQ1OT1, is a long non-coding RNA gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

 found in the KCNQ1 locus

Locus (genetics)

In the fields of genetics and genetic computation, a locus is the specific location of a gene or DNA sequence on a chromosome. A variant of the DNA sequence at a given locus is called an allele. The ordered list of loci known for a particular genome is called a genetic map...

. This locus consists of 8-10 protein-coding genes, specifically expressed from the maternal allele (including the KCNQ1 gene), and the paternally expressed non-coding RNA gene KCNQ1OT1. KCNQ1OT1 is found as a 91 kb transcript in the nucleolus

Nucleolus

The nucleolus is a non-membrane bound structure composed of proteins and nucleic acids found within the nucleus. Ribosomal RNA is transcribed and assembled within the nucleolus...

. It interacts with chromatin

Chromatin

Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell. The primary functions of chromatin are; to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis and prevent DNA damage, and to control gene...

, the histone methyltransferase

Histone methyltransferase

Histone methyltransferases are enzymes, histone-lysine N-methyltransferase and histone-arginine N-methyltransferase, that catalyze the transfer of one to three methyl groups from the cofactor S-Adenosyl methionine to lysine and arginine residues of histone proteins...

 G9a (responsible for the mono- and dimethylation of histone 3 lysine 9, H3K9), and the Polycomb Repressive Complex 2, PRC2

PRC2

PRC2 is one of the two classes of Polycomb-group proteins or . The other component of this group of proteins is PRC1....

, (responsible for the trimethylation of H3K27). It plays an important role in the transcriptional silencing of the KCNQ1 locus by regulating histone methylation. An 890 bp

Base pair

In molecular biology and genetics, the linking between two nitrogenous bases on opposite complementary DNA or certain types of RNA strands that are connected via hydrogen bonds is called a base pair...

 region at the 5'

Directionality (molecular biology)

Directionality, in molecular biology and biochemistry, is the end-to-end chemical orientation of a single strand of nucleic acid. The chemical convention of naming carbon atoms in the nucleotide sugar-ring numerically gives rise to a 5′-end and a 3′-end...

 end of KCNQ1OT1 acts as a silencing domain. This region regulates CpG methylation

DNA methylation

DNA methylation is a biochemical process that is important for normal development in higher organisms. It involves the addition of a methyl group to the 5 position of the cytosine pyrimidine ring or the number 6 nitrogen of the adenine purine ring...

 levels of somatically

Somatic

The term somatic means 'of the body',, relating to the body. In medicine, somatic illness is bodily, not mental, illness. The term is often used in biology to refer to the cells of the body in contrast to the germ line cells which usually give rise to the gametes...

 acquired differentially methylated regions (DMRs), mediates the interaction of KCNQ1OT1 with chromatin and with DNA (cytosine-5)-methyltransferase 1 (DNMT1

DNMT1

DNA -methyltransferase 1 is an enzyme that in humans is encoded by the DNMT1 gene.-Interactions:DNMT1 has been shown to interact with Histone deacetylase 2, DMAP1, PCNA, Retinoblastoma protein, DNMT3A and DNMT3B.-Further reading:...

), but does not affect the interactions of histone methyltransferases with KCNQ1OT1.

Further reading