Albrecht von Arnim
Director, Genome Science and Technology Program
Office: Hesler 228, (865- 974-6206)
Lab: Hesler 230, (865-974-6221)
Ph.D. University of East Anglia (UK)
The past ten years have witnessed a renaissance in our appreciation for the role of RNA in gene regulation. Protein synthesis (translation) in particular remains poorly understood, although translational control affords a rapid means to amplify changes in gene activity that occur at the level of transcription.
We are using the reference plant Arabidopsis thaliana because of the excellent genetic resources available in this species. A reporter gene system was developed to monitor the translation status of specific genes in response to external signals, such as the light environment. We are combining this tool with mutations affecting individual translation initiation factors in an effort to assign specific functions to these proteins in translational control. Our data exemplify that generic initiation factors can contribute to the sequence-specific regulation of translational efficiency. Specifically, we implicated the H subunit of the largest initiation factor, eIF3, in the control of translation by upstream open reading frames, a type of regulatory device present in the 5’ leader of many mRNAs. Furthermore, we have learned how to use the toolkit of genomics, such as microarrays and bioinformatics, to survey the translation status of the entire set of cellular mRNAs. Experiments such as these are poised to reveal systematically which mRNAs are bundled together into regulons of translational control.
This work is helping us to understand how plants respond to their environment, has implications for the mechanisms of translational control in eukaryotes in general, and it may lead to novel ways to manipulate gene expression in the context of biotechnology.
Independently, we are engaged in developing biosensor technology for monitoring specific cellular events, in particular protein-protein interactions. To this end, we are harnessing a biophysical phenomenon, termed bioluminescence resonance energy transfer (BRET), which allows one to measure directly whether and when two proteins associate with each other in a living organism in real time. These and other related biosensors can yield direct and immediate insights into the mechanisms of life in plants and animals.
Missra, A., Ernest, B., Lohoff, T., Jia, Q., Satterlee, J., Ke, K., and von Arnim, A.G. 2015. The circadian clock modulates global daily cycles of mRNA ribosome loading. Plant Cell 27: 2582-2599.
Zhou, F., Roy, B., Dunlap, J.R., Enganti, R., and von Arnim, A.G. 2014. Translational control of Arabidopsis meristem stability and organogenesis by the eukaryotic translation factor eIF3h. PLoS One 9:e95396.
von Arnim, A.G., Jia, Q., Vaughn, J.N. (2014). Review: Regulation of plant translation by upstream open reading frames. Plant Science 214:1-12.
Missra, A and von Arnim, A.G. (2014). Analysis of mRNA translation states over the diurnal cycle by polysome microarray. In: Plant Circadian Networks (Dorothee Staiger, Ed.). Methods in Molecular Biology1158:157-174.
Tiruneh, B.S., Kim, B.H., Gallie, D.R., Roy, B., and von Arnim, A.G. (2013). The global translation profile in a ribosomal protein mutant resembles that of an eIF3 mutant. BMC Biology 11:123.
Roy, B., and von Arnim, A.G. (2013). Translational regulation of cytoplasmic mRNAs. In: The Arabidopsis Book. K Torii and C Chang eds. e0165.
Kim, B.H., Malec, P., Waloszek, A., von Arnim, A.G. (2012). Arabidopsis BPG2: A phytochrome regulated gene whose protein product binds to plastid ribosomal RNAs. Planta 236: 677-690.
Vaughn, J.N., Ellingson, S.R., Mignone, F., and von Arnim, A.G. (2012). Known and Novel Post-Transcriptional Regulatory Sequences are Conserved across Plant Families. RNA 18: 368-384. Plant J. 58:208-19.