Centromeric Sequences and Sequence Structures
Published Online: 17 OCT 2011
Copyright © 2001 John Wiley & Sons, Ltd. All rights reserved.
How to Cite
Koch, J. and Andersen, A. 2011. Centromeric Sequences and Sequence Structures. eLS. .
- Published Online: 17 OCT 2011
Centromere function is essential for the faithful passing on of the parental genome to daughter cells in cell division. This function is carried by specialised noncoding deoxyribonucleic acid (DNA), centromere DNA. The functional DNA element in human centromeres is the α-satellite DNA, which we share with all other primates, but not with nonprimate species. This DNA acts through timed interactions with proteins belonging to the cell-cycle machinery, such as topoisomerase II, which cuts the interconnecting bridges between sister-chromatids to allow and enable the completion of mitotic and second state meiotic cell divisions. To orchestrate these interactions, centromere DNA has the ability to fold into complex three-dimensional shapes, which are the form of the DNA recognised by its protein partners.
Unlike genes coding for proteins, noncoding DNA is not coded in a triplet code where each triplet can be translated into a specific amino acid.
Noncoding DNA is instead coded in the form of spatial structures capable of governing specific interactions with DNA, RNA and proteins in ways that are more reminiscent of antigen–antibody reactions than of the triplet coding.
For this reason scientists have had a hard time understanding what noncoding DNA is good for, at some point even leading to the misconception that it served no good function, but merely was ‘selfish DNA’.
With the discovery of the noncoding RNAs, which are very important for gene regulation, a very different picture is now dawning, and we trust that it will end in the understanding that genes are nothing more than ‘stupid’ data files, whereas the rest of the genome is ‘the software’ reading those data files to produce ‘the hardware’ in the form of gene products.
Centromere DNA is one species of noncoding DNA. It serves its functions through interactions with a whole range of DNA-binding proteins, and to enable the interactions to be ‘on’ or ‘off’ as appropriate, the DNA must be able to turn into different shapes and forms, which are recognised, or not recognised by the various proteins.
- α-satellite DNA;
- centromere DNA;
- centromere function;
- topoisomerase II