Nucleoli form around tandem arrays of a ribosomal gene repeat, termed nucleolar organizer
regions (NORs). During metaphase, active NORs adopt a characteristic undercondensed …

In eukaryotes, the genes encoding ribosomal RNAs (rDNA) exist in two distinct epigenetic
states that can be distinguished by a specific chromatin structure that is maintained …

Publisher Summary This chapter discusses the structure and function of DNA. DNA occupies
a critical role in cells, because it is the source of all intrinsic genetic information. Chemically …

Mammalian cells contain 100 or more copies of tandemly repeated ribosomal RNA (rRNA)
genes per haploid genome. These genes are transcribed with high efficiency to keep up with …

MANY signalling cascades use seven-helical transmembrane receptors coupled to
heterotrimeric G proteins (Gαβγ) to convert extracellular signals into intracellular …

Animal and plant centromeres are embedded in repetitive “satellite” DNA, but are thought to
be epigenetically specified. To define genetic characteristics of centromeres, we surveyed …

The HMG box containing protein UBF binds to the promoter of vertebrate ribosomal repeats
and is required for their transcription by RNA polymerase I in vitro. UBF can also bind in vitro …

All cells, from prokaryotes to vertebrates, synthesize vast amounts of ribosomal RNA to
produce the several million new ribosomes per generation that are required to maintain the …

The rRNAs constitute the catalytic and structural components of the ribosome, the protein
synthesis machinery of cells. The level of rRNA synthesis, mediated by Pol I (RNA …

Publisher Summary This chapter discusses the mechanisms of eukaryotic ribosomal
transcription and its regulation. Ribosomal transcription has been studied in an …