Scientists of the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) have shown that the genetic defect that causes Cockayne Syndrome affects a key function of the cell – the transcription of genes coding for ribosomal RNA.
Cockayne Syndrome is a recessively inherited disorder that belongs to a group of diseases in which defects in one of the numerous DNA repair systems lead to non-functioning proteins and, thus, to severe health impairments. These disorders also include, for example, Xeroderma pigmentosum and a type of hereditary bowel cancer.
However, symptoms of Cockayne Syndrome, which is a very rare disease, are particularly severe, including dwarfism, mental retardation, hearing and vision impairments; affected individuals have a characteristically formed small head, they age prematurely and die younger. The scale of these defects suggested that a dysfunctional DNA repair mechanism alone cannot be responsible for this whole range of impairments.
Cockayne Syndrome is characterized by a defect in the CSB protein, which is the main component of a particular DNA repair system. Research results of several working groups had already suggested that CSB is additionally involved in transcription, i.e. the conversion of DNA to RNA. However, the exact mechanism had remained unknown.
In each cell, various RNA types are responsible for specific tasks. Thus, the so-called rRNA is a key component of the ribosomes, the protein factories of the cell. A research group headed by Professor Dr. Ingrid Grummt of the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) has now shown that CSB is pivotal in the production of rRNA molecules.