Hidden proteins found in bacteria

Scientists at the University of Illinois at Chicago have developed a way to identify the beginning of every gene -- known as a translation start site or a start codon -- in bacterial cell DNA with a single experiment and, through this method, they have shown that an individual gene is capable of coding for more than one protein.

Historically, the generally taught scientific premise has been that each gene has one unique start site and is responsible for the creation of only one protein. However, the study, which is published in Molecular Cell, a leading journal on the topic of cellular processes, shows that some genes have more than one start site and can specify production of more than one functional protein.

Their method of identifying gene start sites relies on a common prescription drug called retapamulin, a topical antibiotic. Retapamulin, they showed for the first time, works by causing the ribosome, which reads genetic code, to become stalled at these start sites, inhibiting translation, a key part of the process by which the genetic code in DNA is used to create proteins.

UIC's Alexander Mankin and Nora Vázquez-Laslop led the research, which looked at E. coli cells in response to retapamulin in in vitro and in vivo experiments. The researchers found more than 100 E. coli genes, out of around 4,000, that could initiate protein synthesis at more than one site.

For further details, see:

Sezen Meydan, James Marks, Dorota Klepacki, Virag Sharma, Pavel V. Baranov, Andrew E. Firth, Tōnu Margus, Amira Kefi, Nora Vázquez-Laslop, Alexander S. Mankin. Retapamulin-Assisted Ribosome Profiling Reveals the Alternative Bacterial Proteome. Molecular Cell, 2019; DOI: 10.1016/j.molcel.2019.02.017

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology