The end is important too
Oeiras, 27.01.14
Living organisms modulate gene expression at multiple levels. Higher organisms are known to stabilize messenger RNA molecules – the protein-coding vehicles – through an untranslated sequence at the end called 3’ UTR. This mechanism seemed to be absent from bacteria. Now, in a recent collaborative work with labs in Spain and France, researchers from the Control of Gene Expression Lab have shown that bacteria control at least some messenger RNA molecules this way. The work is published in PLoS Genetics.
RNA molecules are the working copies of the genome. Messenger RNAs (mRNAs) copy those portions of the DNA that codify for proteins and ensure that the protein is produced. But the level of production of each protein, which in turn affects its activity, depends on the stability, location and translation efficiency of the mRNA molecule. Besides the protein coding sequence, mRNA contain non-coding sequences at either end, which (in particular the so called 3’ end) are known for their regulatory role in higher organism. On the contrary, bacterial 3’UTRs have been largely unnoticed.
Using the bacteria Staphylococcu aureus, researchers analysed all messenger RNA molecules to identify those with longer 3’UTR sequences. From this subgroup researchers concentrated on a specific mRNA, encoding a protein involved in biofilm formation, an essential process for bacterial infection. Researchers then observed what happened to bacteria if this untranslated region was deleted just to find out that biofilm formation was impaired, even though the protein coding region was intact. This observation confirms the regulatory role of 3’UTR in this particular mRNA molecule.
Researchers believe that all bacteria will have potential regulatory 3’-UTRs - in Staphylococcus aureus, at least 35% of the mRNAs have long 3’-UTRs – opening a new perspective to understand the bacterial strategies for fine tuning gene expression.
Original Article
PLOS Genetics | DOI: 10.1371/journal.pgen.1004001
Base Pairing Interaction between 5′- and 3′-UTRs Controls icaR mRNA Translation in Staphylococcus aureus
Igor Ruiz de los Mozos, Marta Vergara-Irigaray, Victor Segura, Maite Villanueva, Nerea Bitarte, Margarida Saramago, Susana Domingues, Cecilia M. Arraiano, Pierre Fechter, Pascale Romby, Jaione Valle, Cristina Solano, Iñigo Lasa, Alejandro Toledo-Arana
Igor Ruiz de los Mozos, Marta Vergara-Irigaray, Maite Villanueva, Nerea Bitarte, Jaione Valle, Cristina Solano, Iñigo Lasa, Alejandro Toledo-Arana Laboratory of Microbial Biofilms. Instituto de Agrobiotecnología (IDAB). Universidad Pública de Navarra-CSIC-Gobierno de Navarra. Campus de Arrosadía. Pamplona, Spain.
Victor Segura Genomics, Proteomics and Bioinformatics Unit. Center for Applied Medical Research. University of Navarra. Pamplona, Spain.
Margarida Saramago, Susana Domingues, Cecilia M. Arraiano Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa. Oeiras, Portugal.
Pierre Fechter, Pascale Romby Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC. Strasbourg, France.
