Current research interests and projects
With grant support from the National Institutes of Health, we are investigating how the small subunit of the ribosome is assembled and exported from the nucleus using the yeast S. cerevisiae as a model organism to study this essential and highly conserved process. Ribosomes are among the largest and most complex macromolecular machines assembled in cells. Ribosomes are assembled from imported ribosomal proteins on nascent rRNA in the nucleolus of the cell. The large and small subunits are then independently exported through nuclear pores at rates that can reach 30 subunits per second. Both subunits require the export receptor Crm1 for export, and both undergo independent post-export maturation events that are required before the subunits are translation-ready. Over 150 proteins that do not end up as constituents of the mature ribosome are necessary for ribosome biogenesis. The molecular details of how most of these non-ribosomal proteins function is unknown.
We have focused our work on the late steps of small subunit biogenesis. In particular, we are characterizing the role of Ltv1, a late adding biogenesis factor, and the role of RpS3, a ribosomal protein that interacts with Ltv1. We hope to understand better what role ribosomal proteins play in ribosome biogenesis and what role Ltv1 plays in both export and subunit maturation.
RpS3 structure in the yeast 40S subunit
Jesse W. Loar*, Robert M. Seiser, Alexandra E. Sundberg*, Holly J. Sagerson*, Nasreen Ilias*, Pamela Zobel-Thropp, Elizabeth A. Craig, and Deborah E. Lycan . (2004) Genetic and biochemical interactions among Yar1, Ltv1 and Rps3 define novel links between environmental stress and ribosome biogenesis in Saccharomyces cerevisiae. Genetics 168 :1877-89.
Robert M. Seiser, Alexandra Sundberg*, Bethany Wollam*, Pamela Zobel-Thropp, Katherine Baldwin*, Maxwell Spector*, and Deborah E. Lycan. (2006) Ltv1 is required for efficient nuclear export of the ribosomal small subunit in Saccharomyces cerevisiae. Genetics 174: 1-13.
Claire A. Fassio*, Brett J. Schofield*, Robert M. Seiser, Arlen W. Johnson and Deborah Lycan. (2010) Dominant mutations in the late 40S biogenesis factor Ltv1 affect cytoplasmic maturation of the small ribosomal subunit in S. cerevisiae. Genetics 185: 199-209.
Jason R. Merwin, Lucien Bogar*, Sarah Poggi*, Rebecca M. Fitch*, Arlen W. Johnson and Deborah E. Lycan (2014) Genetic Analysis of the Ribosome Biogenesis Factor Ltv1 of Saccharomyces cerevisiae. Genetics 198: 1071–1085.