Nucleotide pools and regulation of ribonucleic acid synthesis in yeast

Abstract

Nucleotide pools were measured in growing and amino acid-starved Saccharomyces cerevisiae. During amino acid starvation there are neither significant changes in the endogeneous nucleoside triphosphate pool levels nor measurable synthesis of guanosine 5'-diphosphate, 3'-diphosphate. Stable ribonucleic acid synthesis does not appear to be regulated by changes in the triphosphate pools or by the unusual nucleotide guanosine 5'-diphosphate, 3'-diphosphate.

Growth and differentiation of the water mold Blastocladiella emersonii: cytodifferentiation and the role of ribonucleic acid and protein synthesis.

“…It is not yet entirely clear how tight a coupling exists between the rates of protein and RNA synthesis in fungi (58,133,196,236). Our results with Blastocladiella, if representative, certainly indicate that the rate or rRNA synthesis responds rapidly to changes in the rate of protein synthesis.…”

Control of rRNA transcription in Escherichia coli.

“…However, unlike in the bacterial system, the production of tRNA appears to be exempt from stringent control. The signal for stringent control in S. cerevisiae is also thought to be the accumulation of uncharged tRNA in the cell (236), but there is no evidence of either guanosine tetra-or pentaphosphate synthesis by the cytoplasmic ribosomes (169,245,268). Indeed, this is true for a host of other eukaryotic organisms (cited in references 32 and 245).…”

Cellular nucleotide measurements and applications in microbial ecology.

“…Unlike the ATP pool, which is maintained at a relatively constant level independent ofgrowth rate, the intracellular concentrations of nonadenine NTPs fluctuate in direct proportion to their requirements for biosynthesis (107,169,296,297). In retrospect, this relationship might have been predicted, at least for cellular GTP levels, since (i) the number of sites for protein synthesis (i.e., the ribosomes) increases as a linear function of growth rate and (ii) the rate of protein synthesis does not appear to be limited by GTP concentrations under normal steadystate growth conditions (26,64,199). The intracellular GTP pool must increase as the growth rate increases in order to maintain saturating GTP concentrations at the ribosomes.…”