Does the fact that translation and transcription proceed simulataneously [in prokaryotes] cause problems?
The directions of translation and transcription are such that the first part of the message synthesized (the 5′-end) is the first part translated — as such translation proceeds on a message that is still in the process of being transcribed. Bacteria seem to do fine with this arrangment. It obviously presents some limitations, however, including: – 1. if introns were present [which they almost universally are not], one would need to have a mechanism that would block translation until splicing was completed — the nuclear envelope accomplishes this effectively in eukaryotes. – 2. with this arrangement, virtually all regulation of gene expression must exist at the transcriptional level, eliminating the fine tuning one obtains in eukaryotes from splicing, RNA export, translational efficiency, RNA degradation.
