James Umen, Ph.D.

Using algae as a primary experimental system, Jim’s research is investigating cell size control, cell growth regulation and carbon partitioning, and evolution of multicellularity.

James Umen

He was a Postdoctoral Fellow in the Department of Biology at Washington University in St. Louis, Missouri and an instructor at Guilin Geology College in China. Umen received his Ph.D. in Biochemistry and Biophysics from the University of California – San Francisco and his B.S. in Biology from Stanford University, Palo Alto, California.

Prior to joining the Danforth Center as a member of the Enterprise Rent-A-Car Institute for Renewable Fuels, Jim Umen served as Assistant Professor of the Plant Molecular and Cellular Biology Laboratory at the Salk Institute for Biological Studies.

Research Team

Dianyi Liu, Graduate Student at Washington University in St. Louis

I am working on the cell-size control of Chlamydomonas.

Gavriel Matt, Graduate Student at Washington University in St. Louis

I am using the multicellular green alga, Volvox carteri and the closely related unicellular green alga, Chlamydomonas reinhardtii, as a model system to better understand the evolution of multicellularity and cellular differentiation. Specifically, I am trying to understand the molecular-genetic basis for the differentiation of germ and somatic cells in V. carteri by (1) elucidating the transcriptomic profiles of the two cell-types and (2) characterizing the transcriptional targets of a master regulator of germ-soma differentiation in Volvox, somatic regenerator. By comparing molecular signatures of cellular differentiation in Volvox to orthologous machinery in Chlamydomonas, I will investigate the unicellular origins of differentiated multicellularity.

Yi-Hsiang Chou, Postdoctoral Associate


I am interested in understanding the relationship between mechanisms of cell size control (e.g. cell growth) and of cell cycle regulation (e.g. cell division). A key regulatory pathway called retinoblastoma (RB; retinoblastoma family of tumor suppressors) pathway has been showed to coordinate these two important biological processes in developmental programs. My research focus is to investigate new components involved in RB/MAT3 pathway together with MAT3 (RB homolog in Chlamydomonas reinhardtii) to regulate and balance cell size and cell cycle in Chlamydomonas reinhardtii.

Yu Liu, Postdoctoral Associate 

I am working on the control of carbon partitioning by target of rapamycin pathway and inositol pyrophosphate signaling in Chlamydomonas reinhardtii.

Sa Geng, Research Scientist

I am working on the molecular basis of sex dimporphism and morphogenesis of the multicellular volvocine algae Volvox carteri, and clarifying the RB/Mat3 function diversities through studying the RB/Mat3 repressor pathway evolution in volvocine alage.