Difference Between Polycistronic mRNA and Monocistronic mRNA

RNA stands for ribonucleic acid. There are three types of RNA present in cells; mRNA (messenger RNA), tRNA (transfer RNA, and rRNA (ribosomal RNA). mRNA is classified into two types based on the cells in which they are present and the number of protein codes, they are polycistronic mRNA vs. monocistronic mRNA. mRNA polycistronic is that messenger RNA, encoding two or more proteins to be synthesized, and is present in translation in prokaryotic cells, while monocistronic mRNA is that messenger RNA, encoding only one specific protein or polypeptide, present in the translation in eukaryotic cells.

Comparison chart

What is polycistronic mRNA?

Poly means “many” and cistron means “genes.” An mRNA is called a polycistronic mRNA when it codes for two or many proteins; contains more than one gene code in it. Polycistronic mRNA contains many cistron codons. When it is transcribed in cells, it has many codons that start this process and many codons that end it. The translation-initiating coding region consists primarily of a linear structure or sequence of codons. These codons make it polyfunctional for the cell. Furthermore, these RNAs have multiple ORFs (open reading frames), each of which corresponds to the transcript of a single gene. These codons or ORFs are then translated into a polypeptide according to the code. This mRNA is mainly present in prokaryotes like bacteria etc.

What is monocistronic mRNA?

Mono means “one” and cistron means “genes.” An mRNA is called a monocistronic mRNA when it encodes only individual proteins; contains only one gene code. Monocistronic mRNA contains a single codon of a cistron. When it is transcribed in the cell, it only has one codon that starts this process and one codon that ends it. The translation-initiating coding region consists primarily of a linear structure or sequence of codons. These codons make it monofunctional for the cell. Furthermore, these RNAs have a single ORF (open reading frame), each of which corresponds to a unique or specific gene transcript. These codons or ORFs are then translated into a polypeptide according to the code. Monocistronic mRNA is present in eukaryotes like human cells. Many eukaryotic RNAs are nonfunctional and require many types of changes (post-transcriptional changes). These changes can be like splicing, splicing, intron removal, etc.

Polycistronic vs. Monocistronic mRNA

• Polycistronic mRNA is the messenger RNA that encodes two or more proteins while monocistronic mRNA is that messenger RNA that encodes only one specific protein or polypeptide.
• Polycistronic mRNA contains many cistron codons while monocistronic mRNA contains only one cistron codon.
• Polycistronic mRNA has many codons that start this process, and many codons that stop and counteract them, this monocistronic mRNA has only one codon that starts this process and one codon that stops them.
• Polycistronic mRNA has multiple ORFs (open reading frames), while monocistronic mRNA has a single ORF (open reading frame).
• Polycistronic mRNA is mainly present in prokaryotes like bacteria while monocistronic mRNA is present in eukaryotes like human cells.
• Polycistronic mRNA does not require post-transcriptional changes, while monocistronic mRNA requires post-transcriptional changes.