Arabidopsis thaliana is a species grown worldwide for genetic research and was the first plant to have its complete set of chromosomes (its genome) sequenced.
These ribosomal RNA gene clusters, known as nucleolus organizer regions (NORs), are not just difficult to define in Arabidopsis; gaps remain at the NORs in the genome sequences of nearly all eukaryotes (organisms whose cells have a nucleus), including humans. This has stymied studies of the NORs, and the genes within them, which encode the RNAs of ribosomes, the protein-synthesizing machines of all living cells.
The ribosomal RNA genes are regulated in ways that are not fully understood. For instance, they are known to be under epigenetic control, meaning that they can be turned on or off in a manner that does not depend on their sequence, but it is not clear how. And mis-regulation of the genes occurs in many cancers.
As a result, an understanding of ribosomal RNA gene regulation has long been a focus of biomedical research funding, which includes studies in plants, yeast, fruit flies, mice and other model organisms.
A new study, published in Science Advances, reports the complete sequences for the two Arabidopsis NORs and how active and silent ribosomal RNA genes are distributed throughout the NORs. The paper was authored by postdoctoral researchers Dalen Fultz, Anastasia McKinlay and Ramya Enganti in the laboratory of Craig S. Pikaard, an Investigator of the Howard Hughes Medical Institute and a Distinguished Professor, and Carlos O. Miller Professor, in the Departments of Biology and Molecular and Cellular Biochemistry at Indiana University Bloomington (IUB). Previous studies by the lab had shown that active and silent ribosomal RNA genes subtypes co-exist but associated with different NORs, based on genetic tests.
2023-12-16 20:41:03
Original from phys.org rnrn
