Transcribing Wisely

Science's STKE  23 May 2000:
Vol. 2000, Issue 33, pp. tw8
DOI: 10.1126/stke.2000.33.tw8

In yeast, as much as 50 to 60% of all transcription events can be devoted to the production of protein-synthesizing machinery (rRNAs, ribosomal proteins, and tRNAs). Thus, regulation of the synthesis of this machinery is essential to survival under adverse conditions. The cell integrity pathway, which mediates the response to increases in osmotic pressure, has been implicated in the repression of transcription of the rRNAs by RNA polymerase I and the ribosomal protein RNAs by RNA polymerase II. Li et al. show that transcription of the tRNAs by RNA polymerase III is also inhibited in temperature-sensitive secretory pathway mutants in yeast. However, they provide evidence that the pathway mediating this repression diverges from the cell integrity pathway downstream of protein kinase C and, subsequently, branches again, allowing specific regulation of each of the three polymerases.

Li, Y., Moir, R.D., Sethy-Coraci, I.K., Warner, J.R., and Willis, I.M. (2000) Repression of ribosome and tRNA synthesis in secretion-defective cells is signaled by a novel branch of the cell integrity pathway. Mol. Cell. Biol. 20: 3843-3851. [Abstract] [Full Text]