Wednesday 9 November 2016 - Toxic DNA: a model for all domains of life
The conventional view of transcription is that mRNAs are generated from the coding DNA strand and are delineated by gene boundaries; however, recent reports have mapped transcription start sites to unexpected locations in bacterial genomes, including the non-coding strand. The resultant RNAs were previously dismissed as artefacts, but models that describe such events as 'pervasive transcription' are now gaining support. We have found that DNA with an atypical base composition is particularly prone to these pervasive transcriptional effects. This explains the long standing observation that certain DNA sequences, particularly those that are AT-rich, can be toxic to the cell. I will discuss the underlying molecular mechanisms and provide a model that could be applicable to all forms of life.