HOTAIR

HOTAIR (for HOX transcript antisense RNA) is a human is_associated_with::gene located on is_associated_with::chromosome 12. It is the first example of an RNA expressed on one chromosome that has been found to influence transcription on another chromosome.

Gene and transcribed RNA product
The HOTAIR gene contains 6,232 bp and encodes 2.2 kb is_associated_with::long noncoding RNA molecule, which controls gene expression. Its source is_associated_with::DNA is located within a HOXC is_associated_with::gene cluster. It is shuttled from chromosome 12 to chromosome 2 by the Suz-Twelve protein.

Function
The 5' end of HOTAIR interacts with a is_associated_with::Polycomb-group protein Polycomb Repressive Complex 2 (is_associated_with::PRC2) and as a result regulates is_associated_with::chromatin state. It is required for gene-silencing of the HOXD locus by PRC2. The 3' end of HOTAIR interacts with the is_associated_with::histone is_associated_with::demethylase is_associated_with::LSD1.

It is an important factor in the is_associated_with::epigenetic differentiation of skin over the surface of the body. Skin from various anatomical positions is distinct, e.g. the skin of the eyelid differs markedly from that on the sole of the foot.

Clinical significance
HOTAIR is highly expressed in is_associated_with::metastatic breast cancers. High levels of expression in primary breast tumours are a significant predictor of subsequent metastasis and death. It is also involved in esophageal squamous cell carcinoma.