Heat-shock induction and cytoplasmic localization of transcripts from telomeric-associated sequences in Chironomus thummi.

Transcription of telomeric-associated sequences has been detected in the salivary gland cells of the larvae Chironomus thummi. In this species, a heat shock induces puffing at some telomeres, especially at one of the telomeres of chromosome III. We found that this process was concomitant with an increase in the overall telomeric transcript levels. Transcription was also observed in all the telomeres under control conditions, by in situ hybridization, even when these telomeres appeared to be in a nonpuffed state. The telomeric transcripts were found in both, the nuclei and, at higher levels, in the cytoplasmic extracts of salivary gland cells. The heat-shock activation, however, appeared to be restricted to the nuclear level. Telomeric transcription and the peculiar behavior of C. thummi telomeres after a heat shock are discussed.