Polycistronic

Polycistronic mRNA is the term give to a molecule that comprises coding sequences for many different polypeptide chains (cistron is the term given to a nucleotide sequence that only contains conding sequences for one polypeptide chain). Furthermore, in polycistronic mRNA each region that contains a sequence for a different polypeptide is preceded by a ribosome binding site, and also an AUG start codon. Often, the different coding sequences in a polycistronic molecule encode for the different proteins that occur in metabolic pathways.