The Expression of the HSP70 Gene in Moneuplotes crassus is Controlled by a Two‐Step Process at the Transcript Level

Abstract

Steady state levels of the HSP70 transcript were followed by Northern hybridization in Moneuplotes crassus in order to investigate the mechanisms of the short term and long term response to heat shock in a spirotrichous ciliate. The influence of inhibitors of transcription or translation on the transcript levels was also studied. The heat shock response could be dissected into two phases. An initial protein-dependent stabilization of the mRNA was followed by an increase of the steady state transcript level that was dependent on continued transcription. As expected, the half-life of the RNA was short. Western blot analysis then showed that the HSP70 protein accumulated only upon permanent heat shock. It is concluded that the regulation of the heat shock response is a two-step process that occurs at the transcript level.

α-Tubulin Minichromosome Promoters in the Stichotrichous Ciliate Stylonychia lemnae

“…Despite this relevance and despite evidence that ciliates regulate their genes at the transcriptional level (2,36,37), determinants of transcription in these organisms have not been a major focus. In Tetrahymena thermophila, promoter elements have been experimentally identified in the rRNA gene (6,25), the telomerase RNA gene (11), and the RAD51 gene (35).…”