Faculty and Research
Faculty by Name
Nicole King
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Nicole King
Assistant Professor of Genetics, Genomics and Development
Lab Homepage: http://kinglab.berkeley.edu/
Research Interests
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We study choanoflagellates and the evolution of multicellular animals from their unicellular ancestors.
The origin of animals represents one of the pivotal transitions in life's history, and one of its greatest unsolved mysteries. While the fossil record remains silent regarding the rise of multicellularity, the genetic and developmental foundations of animal origins may be deduced from shared elements among extant animals and their protozoan relatives, the choanoflagellates. To better understand the origin and evolution of animals, our goals are to [1] determine the minimal genomic complexity of the common ancestor of animals, [2] elucidate the ancestral functions of genes required for multicellular development, [3] characterize choanoflagellate cell and developmental biology, and [4] test the hypothesis that the emergence of multicellular animals stemmed, in part, from the evolution of new modes of gene regulation.
Current Projects
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Using comparative genomics to investigate the ancestral animal genome
A key question in the origin of animals concerns how and when the "toolkit" of animal genes was assembled. To test whether genes required for animal development evolved before the origin of animal multicellularity, we are comparing sets of genes expressed by choanoflagellates, animals, Fungi, Plants, and unicellular eukaryotes. Genes shared only by choanoflagellates and animals were likely present in their common ancestor and may shed light on the transition to multicellularity. This work has already provided evidence for the expression in choanoflagellates of protein families (e.g. receptor tyrosine kinases, cadherins, and C-type lectins) required for animal cell signaling and adhesion. Our current goals are to characterize the diversity of genes encoding transcription factors, signaling and adhesion genes, and cytoskeletal components in choanoflagellates, and to examine the history of certain protein families prior to the origin of animals.
Assaying the ancient functions of genes required for multicellular development
The finding of signaling and adhesion gene homologs (e.g. cadherins and receptor tyrosine kinases) in choanoflagellates raises questions about how these genes functioned in the unicellular common ancestor of choanoflagellates and animals, and what role they played in the origin of multicellularity. To determine the function of specific genes in choanoflagellates, we are developing techniques for manipulating gene activity in vivo. Inferences about gene function in diverse choanoflagellates provide an important reference point for studies of gene family evolution in animals.
Cell and developmental biology of choanoflagellates
The mechanisms by which choanoflagellates form colonies, establish cell polarity, and reproduce should provide crucial insights into the transition to multicellularity, but little is known about their cell or natural history. Therefore, we are examining the life cycles of diverse choanoflagellates using techniques ranging from classical protistology to electron and immunofluorescence microscopy to bioinformatics.
Selected Publications
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Westbrook MJ, Larroux, C, Degnan, B, King, N. (2009). Intron loss and the evolution of exceptionally long genes in choanoflagellates, sponges, and eumetazoans. In review.
Nichols SA, Dayel MJ, and King N. (2009) Genomic, phylogenetic, and cell biological insights into metazoan origins in Animal Evolution: Genes, Genomes, Fossils and Trees (Ed. MJ Telford and DTJ Littlewood, Oxford University Press).
King N, Young SL, Abedin M, Carr M, and Leadbeater BSC (2008) The choanoflagellates: heterotrophic nanoflagellates and the sister group of the Metazoa in Emerging Model Organisms (Cold Spring Harbor Laboratory Press). v.1.
Grimson A, Srivastava M, Fahey B, Woodcroft BJ, Chiang HR, King N, Degnan BM, Rokhsar DS & Bartel DP (2008) Early origins and evolution of microRNAs and Piwi-interacting RNAs in animals. Nature 455(7217):1193-7.
Kodner RB, Summons RE, Pearson A, King N, and Knoll AH (2008) Sterols in a unicellular relative of the metazoans. PNAS 105(29):9897-902.
Li W, Young SL, King N, Miller WT. (2008) Signaling properties of a non-metazoan Src kinase and the evolutionary history of Src negative regulation. JBC 283(22):15491-501.
N. King, M.J. Westbrook*, S.L. Young*, A. Kuo, M. Abedin, J. Chapman, S. Fairclough, U. Hellsten, Y. Isogai, I. Letunic, M. Marr, D. Pincus, N. Putnam, A. Rokas, K. J. Wright, R. Zuzow, W. Dirks, M. Good, D. Goodstein, D. Lemons, W. Li, J. Lyons, A. Morris, S. Nichols, D. J. Richter, A. Salamov, JGI Sequencing, P. Bork, W.A. Lim, G. Manning, W.T. Miller, W. McGinnis, H. Shapiro, R. Tjian, I.V. Grigoriev, D. Rokhsar. (2008) The genome of the choanoflagellate Monosiga brevicollis and the origins of metazoan multicellularity. Nature 451(7180):783-8.
M. Abedin and N. King. (2008) The premetazoan ancestry of cadherins. Science 319(5865):946-8.
Iñaki Ruiz-Trillo, Gertraud Burger, Peter W. H. Holland, Nicole King, B. Franz Lang, Andrew J. Roger and Michael W. Gray. (2007) The origins of multicellularity: a multi-taxon genome initiative. Trends in Genetics 23(3):113-8.
Nichols S.A., Dirks, W., Pearse, J.S., and King N. (2006) Early evolution of animal cell signaling and adhesion genes. PNAS 103(33):12451-6.
King, N. (2004) The unicellular ancestry of animal development. Developmental Cell 7(3): 313-25.
King, N., Hittinger, C.T., and Carroll, S.B. (2003) Evolution of key cell signaling and adhesion protein families predated the origin of animals. Science 301(5631):361-3.
Rokas, A.R.*, Williams B.L.*, King, N. and Carroll, S.B. (2003) Genome-scale approaches to resolving incongruence in molecular phylogenies. Nature 425 (6960):798-804.
King, N. and Carrroll, S.B. (2001) A receptor tyrosine kinase from choanoflagellates: Molecular insights into early animal evolution. PNAS 98: 15032–15037.
Last Updated 2009-08-25