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The official name of this gene is “origin recognition complex, subunit 6.”
ORC6 is the gene's official symbol. The ORC6 gene is also known by other names, listed below.
The ORC6 gene provides instructions for making a protein that is important in the copying of a cell's DNA before the cell divides (a process known as DNA replication). The protein produced from this gene is one of a group of proteins known as the origin recognition complex (ORC). (The complex is made up of the proteins ORC1 to ORC6, which are produced from different genes.) ORC attaches (binds) to certain regions of DNA known as origins of replication (or origins), where the process of DNA copying begins. This complex attracts additional proteins to bind to it, forming a larger group of proteins called the pre-replication complex. When the pre-replication complex is attached to the origin, replication is able to begin at that location. This tightly controlled process, called replication licensing, helps ensure that DNA replication occurs only once per cell division and is required for cells to divide.
ORC also attaches to a form of DNA called heterochromatin. Heterochromatin is densely packed DNA that contains few functional genes, but it is important for controlling gene activity and maintaining the structure of chromosomes. It is unclear what effect ORC binding has on heterochromatin.
In addition to its roles as part of ORC, the ORC6 protein is involved in the process by which the dividing cells separate from one another (cytokinesis).
At least two mutations in the ORC6 gene have been found to cause Meier-Gorlin syndrome, a condition characterized by short stature, underdeveloped kneecaps, and small ears. One mutation changes a single protein building block (amino acid) in the ORC6 protein, replacing the amino acid tyrosine at protein position 232 with the amino acid serine (written as Tyr232Ser). The other gene mutation leads to production of an abnormally short protein. These changes impair assembly of the pre-replication complex, disrupting replication licensing; however, it is not clear how a reduction in replication licensing leads to Meier-Gorlin syndrome. Researchers speculate that such a reduction delays the cell division process, which slows growth of the bones and other tissues during development. Some studies suggest that alterations of ORC6 impair cytokinesis, which may also delay cell division. It is not known why development of the kneecaps and ears is particularly delayed.
Cytogenetic Location: 16q12
Molecular Location on chromosome 16: base pairs 46,689,645 to 46,698,393
The ORC6 gene is located on the long (q) arm of chromosome 16 at position 12.
More precisely, the ORC6 gene is located from base pair 46,689,645 to base pair 46,698,393 on chromosome 16.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about ORC6 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
amino acid ; cell ; cell division ; cytokinesis ; DNA ; DNA replication ; gene ; heterochromatin ; mutation ; protein ; serine ; short stature ; stature ; subunit ; syndrome ; tyrosine
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.