In E. coli bacterium, the RNA polymerase has co-factors and along with (sigma) factor, to catalyse the process. The transcription is completed in three steps.

Initiation, (sigma) factor, recognises the start signal and promoter region on DNA which then along with RNA polymerase binds to the promoter to initiate transcription.
Elongation: The RNA polymerase after initiation of RNA transcription loses the factor but continues the polymerisation of ribonucleotides to form RNA.
Termination: Once the RNA polymerase reaches the termination region of DNA, the RNA polymerase is separated from DNA-RNA hybrid, as a result nascent RNA separates. This process is called termination which is facilitated by a termination factor (rho).
In prokaryotes, mRNA does not require any processing, so both transcription and translation occur in the cytosol. It can be said that transcription and translation are coupled together.

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