In what process is mRNA synthesized

Transcription is the process by which DNA is copied (transcribed) to mRNA, which carries the information needed for protein synthesis. Transcription takes place in two broad steps ... The pre-messenger RNA is then "edited" to produce the desired mRNA molecule in a process called RNA splicing.

During transcription, the RNA polymerase read the template DNA strand in the 3'→5' direction, but the mRNA is formed in the 5' to 3' direction. The mRNA is single-stranded and therefore only contains three possible reading frames, of which only one is translated.