mRNA is transcribed from DNA template containing protein coding genes. They carry genetic information in the form of triplet code of three nucleotide sequence from DNA in the nucleus to the site of protein synthesis in the cytoplasm. With the help of other two types of RNAs (rRNA and tRNA), mRNA is translated into polypeptide chain. Genes are only expressed when genetic information in DNA is transcribed into mRNA and then it (mRNA) is translated into proteins.
