Post-transcriptional modification in prokaryotes
There is very little post-transcriptional modification in prokaryotes. As a result, post-transcriptional modification has only a minor influence on gene expression in prokaryotes.
Translation usually occurs immediately after an mRNA strand has been transcribed, so there is no opportunity for post-transcriptional modification. Both translation and transcription occur in the cytosol.
Post-transcriptional modification does, however, frequently occur in the production of prokaryotic rRNA and tRNA.
In this case, transcription is not followed by translation, so there is time to perform modifications.