Species Human Entrez 113510 | Human Mouse Ensembl ENSG00000163312 | |
Aliases HELQ, HEL308, helicase, POLQ-like External IDs MGI: 2176740 HomoloGene: 14667 GeneCards: HELQ | ||
Helicase, POLQ-like, also known as hel308 and Holliday junction migration protein, encoded by the gene HEL308, is a DNA helicase found in humans, archea and many other organisms. Its principal function is to allow DNA replication to continue past DNA forks.
Contents
Gene
The gene encoding this enzyme, HEL308, is located on chromosome 4q21 in humans. It is associated with the polymerase pathway.
Nomenclature
When first reported, Hel308 was called "Holliday junction migration protein." It is also called HelQ in Caenorhabditis elegans and humans.
Like many proteins, Hel308 was named after a previously discovered protein to which it had some connection. In this case, the "Hel" stands for "human helicase" and the "308" is a reference to the Drosophila melanogaster protein Mus308, to which it is homologous.
Classification
Hel308 is part of DNA helicase superfamily II, a group of enzymes that wind and unwind DNA. Hel308 is found throughout archea and in some eukaryotes, including humans. It contains twenty exons.
Structure and function
Hel308's principal role is to repair replication-blocking lesions, such as interstrand DNA cross-links that interfere with the forking of DNA during replication.
Hel308 is a large protein, 1101 amino acids in length, with five separate domains. The third and fourth domains form a large central pore that holds single-stranded DNA. Its fifth domain acts as a brake by securing the single-strand DNA protruding through this pore.
Clinical significance
Mutations in HEL308 are associated with cancer of the pharynx and mouth.