Crosstalk in gene expression: coupling and co-regulation of rDNA transcription, pre-ribosome assembly and pre-rRNA processing.
Ribosomes, the large RNPs that translate mRNA into protein in the cytoplasm of eukaryotic cells, are synthesized in a subcompartment of the nucleus, the nucleolus. There, transcription by Pol I yields a pre-rRNA which is modified, cleaved and assembled with ribosomal proteins to make functional ribosomes. Previously, rRNA transcription and pre-rRNA cleavage in eukaryotes were considered to be separable steps in gene expression. However, recent findings suggest that these two steps in gene expression can be concurrent and are co-regulated. Unexpectedly, optimal rDNA transcription requires the presence of a defined subset of components of the pre-rRNA processing machinery.
Granneman
Sander
S
Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Baserga
Susan J
SJ
D000818:Animals; D005786:Gene Expression Regulation / Q000502:physiology; D020459:Genes, rRNA / Q000235:genetics*; D008954:Models, Biological; D012318:RNA Polymerase I / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D020718:Ribonucleoproteins, Small Nucleolar / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D012335:RNA, Ribosomal; D020718:Ribonucleoproteins, Small Nucleolar; D012318:RNA Polymerase I