messenger RNA

(noun)

Messenger RNA (mRNA) is a molecule of RNA that encodes a chemical "blueprint" for a protein product.

Related Terms

Examples of messenger RNA in the following topics:

  • The Central Dogma: DNA Encodes RNA and RNA Encodes Protein

    • The central dogma of molecular biology describes the flow of genetic information in cells from DNA to messenger RNA (mRNA) to protein.
    • If the transcribed gene encodes a protein, the result of transcription is messenger RNA (mRNA), which will then be used to create that protein in the process of translation.
    • Transfer RNA, or tRNA, translates the sequence of codons on the mRNA strand.
    • Instructions on DNA are transcribed onto messenger RNA.
    • Ribosomes are able to read the genetic information inscribed on a strand of messenger RNA and use this information to string amino acids together into a protein.

  • RNA Splicing

    • Alternative splicing can occur due to the different ways in which an exon can be excluded from or included in the messenger RNA.
    • The pattern of splicing and production of alternatively-spliced messenger RNA is controlled by the binding of regulatory proteins (trans-acting proteins that contain the genes) to cis-acting sites that are found on the pre-RNA.
    • Proteins that are translated from alternatively-spliced messenger RNAs differ in the sequence of their amino acids which results in altered function of the protein.
    • The splicing of messenger RNA is accomplished and catalyzed by a macro-molecule complex known as the spliceosome.
    • Equally as important are the silencers and enhancers that are found on the messenger RNAs, also known as cis-acting sites.

  • Types of RNA

    • This intermediary is the messenger RNA (mRNA).
    • Instead, another type of RNA called transfer RNA (tRNA) needs to translate the information from the mRNA into a usable form.
    • The tRNA attaches to the mRNA, but with the opposite base pairings.
    • The ribosome acts like a giant clamp, holding all of the players in position, and facilitating both the pairing of bases between the messenger and transfer RNAs, and the chemical bonding between the amino acids.
    • These subunits do not carry instructions for making a specific proteins (i.e., they are not messenger RNAs) but instead are an integral part of the ribosome machinery that is used to make proteins from mRNAs.

  • The Relationship Between Genes and Proteins

    • Some genes encode structural and regulatory RNAs.
    • There is increasing evidence from research that profiles the transcriptome of cells (the complete set all RNA transcripts present in a cell) that these may be the largest classes of RNAs produced by eukaryotic cells, far outnumbering the protein-encoding messenger RNAs (mRNAs), but the 20,000 protein-encoding genes typically found in animal cells, and the 30,o00 protein-encoding genes typically found in plant cells, nonetheless have huge impacts on cellular functioning.
    • Transcription makes RNA from DNA.
    • The enzyme RNA polymerase creates an RNA molecule that is complementary to a gene-encoding stretch of DNA.
    • Translation makes protein from mRNA.

  • Processing of tRNAs and rRNAs

    • The tRNAs and rRNAs are structural molecules that have roles in protein synthesis; however, these RNAs are not themselves translated.
    • One contains just the pre-rRNA that will be processed into the 5S rRNA; the other spans the 28S, 5.8S, and 18S rRNAs.
    • The 60S subunit is composed of the 28S rRNA, 5.8S rRNA, 5S rRNA, and 50 proteins.
    • The anticodon is a three-nucleotide sequence, unique to each different tRNA, that interacts with a messenger RNA (mRNA) codon through complementary base pairing.
    • Describe how pre-rRNAs and pre-tRNAs are processed into mature rRNAs and tRNAs.

  • The Nucleus and Ribosomes

    • Ribosomes, large complexes of protein and ribonucleic acid (RNA), are the cellular organelles responsible for protein synthesis.
    • They receive their "orders" for protein synthesis from the nucleus where the DNA is transcribed into messenger RNA (mRNA).
    • This mRNA travels to the ribosomes, which translate the code provided by the sequence of the nitrogenous bases in the mRNA into a specific order of amino acids in a protein .

  • Virus Classification

    • The most commonly-used classification method today is called the Baltimore classification scheme which is based on how messenger RNA (mRNA) is generated in each particular type of virus.
    • Viruses may use either DNA or RNA as their genetic material.
    • Viruses can contain double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), double-stranded RNA (dsRNA), single-stranded RNA with a positive polarity (ssRNA), ssRNA with a negative polarity, diploid (two copies) ssRNA, and partial dsDNA genomes.
    • Positive polarity means that the genomic RNA can serve directly as mRNA and a negative polarity means that their sequence is complementary to the mRNA .
    • (a) Rabies virus has a single-stranded RNA (ssRNA) core and an enveloped helical capsid, whereas (b) variola virus, the causative agent of smallpox, has a double-stranded DNA (dsDNA) core and a complex capsid.

  • DNA and RNA

    • This intermediary is the messenger RNA (mRNA).
    • Other types of RNA—like rRNA, tRNA, and microRNA—are involved in protein synthesis and its regulation.
    • DNA and RNA are made up of monomers known as nucleotides.
    • DNA contains A, T, G, and C whereas RNA contains A, U, G, and C.
    • The pentose sugar in DNA is deoxyribose and in RNA it is ribose.

  • Basic Techniques to Manipulate Genetic Material (DNA and RNA)

    • Unlike DNA, which is located in the nucleus of eukaryotic cells, RNA molecules leave the nucleus.
    • The most common type of RNA that is analyzed is the messenger RNA (mRNA) because it represents the protein-coding genes that are actively expressed.
    • RNA analysis is performed to study gene expression patterns in cells.
    • Similar to DNA, RNA extraction involves the use of various buffers and enzymes to inactivate macromolecules and preserve the RNA.
    • Distinguish among the basic techniques used to manipulate DNA and RNA

  • Steps of Virus Infections

    • DNA viruses usually use host cell proteins and enzymes to make additional DNA that is transcribed to messenger RNA (mRNA), which is then used to direct protein synthesis.
    • RNA viruses usually use the RNA core as a template for synthesis of viral genomic RNA and mRNA.
    • The viral mRNA directs the host cell to synthesize viral enzymes and capsid proteins, and to assemble new virions.
    • To convert RNA into DNA, retroviruses must contain genes that encode the virus-specific enzyme reverse transcriptase, which transcribes an RNA template to DNA.
    • RNA and proteins are made and assembled into new virions.