Green Algae Reveal One mRNA Encodes Many Proteins

Researchers discover previously unknown similarity between algae and bacteria.

The Science

In green algae, researchers found multiple instances of two or more proteins translated from a single messenger RNA (mRNA). This suggests two or more genes are being encoded on a mRNA (polycistronic). The idea counters the long-held belief that in eukaryotes, a single gene makes mRNA, which encodes a single protein.

The Impact

The team led by Sabeeha Merchant of the University of California (UC)–Berkeley and including researchers at UC–Los Angeles and Brookhaven National Laboratory discovered this previously unknown similarity between algae and bacteria. Their work was enabled through the Joint Genome Institute–Environmental Molecular Sciences Laboratory (JGI-EMSL) collaborative science initiative called Facilities Integrating Collaborations for User Science (FICUS).


Researchers found polycistronic gene expression is common in the green algae Chlamydomonas reinhardtii and Chromochloris zofingiensis. This ability to encode multiple genes in a single mRNA could improve processes for engineering algae to produce biofuels and other bioproducts. The team’s findings also contribute to larger questions focused on the role of conserved plant genes in photosynthesis, insight which could help improve the growth of sustainable bioenergy crops, especially under stressful conditions.

Principal Investigator(s)

Sabeeha S. Merchant
University of California–Berkeley


This work was supported by the Office of Biological and Environmental Research, within the U.S. Department of Energy (DOE) Office of Science, Awards DE-SC0018301 for Chromochloris zofingiensis and DE-FC02-02ER63421 for Chlamydomonas reinhardtii. Proteomics analyses were performed under the Facilities Integrating Collaborations for User Science (FICUS) Program Proposals 49262, 49840, 49960, and 50797 and used resources at the DOE Joint Genome Institute (JGI) and the DOE Environmental Molecular Sciences Laboratory (EMSL; grid.436923.9), which are DOE Office of Science user facilities. The work conducted by DOE JGI is supported by DOE Office of Science Contract DE-AC02-05CH11231. The work conducted by EMSL is supported by DOE Office of Science Contract DE-AC05-76RL01830. In vitro translation analysis was supported in part by the DOE Office of Basic Energy Sciences Award DE-SC0017035. The ChIP-Seq analysis was supported by a European Molecular Biology Organization Fellowship ALTF 653-2013 (to D.S.). K.K.N. is an investigator at the Howard Hughes Medical Institute.


Gallaher, S.D. et al. “Widespread Polycistronic Gene Expression in Green Algae.” Proceedings of the National Academy of Sciences USA 118(7), e2017714118 (2021). [DOI:10.1073/pnas.2017714118]