Postodoctoral, Washington University, 1999
Ph.D., Biology, Massachusetts Institute of Technology, 1991
B.S., Chemistry, Case Western Reserve University, 1984
One of the most remarkable attributes of developmentally complex organisms is that they start life as a single cell but ultimately produce many different cell types. The generation of cellular diversity can be driven by intrinsic factors, whereby asymmetries are established in the pre-divisional cell and daughters are quantitatively and/or qualitatively different at birth, or it can be driven by extrinsic factors that signal equivalent daughters to develop differently.
Our laboratory investigates cell-intrinsic mechanisms of differentiation, using a simple model, the green alga Volvox carteri. V. carteri has many attributes to recommend it for such studies, including the following: (1) it possesses just two cell types, germ and soma, and hence displays the simplest type of division of labor; (2) it reproduces rapidly, with each adult generating ~16 new asexual progeny in just two days; (3) mutants defective for cell differentiation are easy to isolate, because V. carteri is genetically haploid; and (4) cloning and molecular analysis of genes regulating cellular differentiation in V. carteri has been facilitated by the development of many tools, including a sequenced genome. Current work in our lab focuses on genes required to set aside progenitors of the two cell types during embryogenesis, and on genes required for the maintenance of the somatic cell fate.
V. carteri is closely related to extant taxa that are even simpler than it is, including unicellular Chlamydomonas reinhardtii, which is also a tractable model organism. SinceV. carteri has been diverging from these species for only ~1/10th the time that animals and land plants have been evolving from their respective closest unicellular cousins, these green algae comprise an especially promising system for analyzing the evolution of developmental complexity. Accordingly, we are using genes that are required for cellular differentiation in V. carteri to trace the molecular genetic origins of cell-fate determination in the family of green algae to which it and C. reinhardtii belong.
Nishii, I., and Miller, S.M. (2010) Volvox: simple steps to developmental complexity? Curr. Opin. Plant Biol. 13:1-8.
Nordhues A., Miller S.M., Mühlhaus T., Schroda M. (2010) New insights into the roles of molecular chaperones inChlamydomonas and Volvox. Int. Rev. Cell Mol. Biol. 285:75-113.
Miller, S. M. (2010) Volvox, Chlamydomonas, and the Evolution of Multicellularity. Nature Education 3(9):65
Prochnik SE, Umen J, Nedelcu AM, Hallmann A, Miller SM, Nishii I, Ferris P, Kuo A, Mitros T, Fritz-Laylin LK, Hellsten U, Chapman J, Simakov O, Rensing SA, Terry A, Pangilinan J, Kapitonov V, Jurka J, Salamov A, Shapiro H, Schmutz J, Grimwood J, Lindquist E, Lucas S, Grigoriev IV, Schmitt R, Kirk D, Rokhsar DS. (2010) Genomic analysis of organismal complexity in the multicellular green alga Volvox carteri. Science 329(5988):223-6.
Pappas, V. and Miller, S.M. (2009) Functional analysis of the asymmetric division protein GlsA. Mech. Dev. 126:842-51.
Duncan L, Nishii I, Harryman A, Buckley S, Howard A, Friedman NR, Miller SM. (2007) The VARL gene family and the evolutionary origins of the master cell-type regulatory gene, regA, in Volvox carteri. J. Mol. Evol. 65:1-11.
Duncan, L, Nishii, I., Howard, A, Kirk, D., and Miller, S.M. (2006) Orthologs and paralogs of regA, a master cell-type regulatory gene in Volvox carteri. Curr. Genet. 50:61-72.
Cheng, Q., Balzer, E., Yoshida, M., Wong, J.C., and Miller, S.M. (2006) Effect of histone deactylase inhibitors on tubulin acetylation and development in Volvox carteri. J. Phycol. 42:417-22.
Cheng, Q., Hallmann, A., Edwards, L., and Miller, S.M. (2006) Characterization of a heat-shock inducible hsp70 gene of the green alga Volvox carteri. Gene 371:112-120.
Cheng, Q., Pappas, V., Hallmann, A., and Miller, S.M. (2005) Hsp70A and GlsA interact as chaperone partners to regulate asymmetric cell division in Volvox. Dev. Biol. 286:537-48.
Cheng, Q., Fowler, R., Tam, L-W., Edwards, L., and Miller, S.M. 2003. The role of GlsA in the evolution of asymmetric cell division in the green alga Volvox carteri. Dev. Genes Evol. 213:328-335.
Miller, S.M. 2002. Taming the fierce roller: an “enhanced” understanding of cellular differentiation in Volvox. Bioessays 24:1-5.