Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
Ryan E Hulett
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
Daniel Chan
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
Grant A King
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
Reef Aldayafleh
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
David S Booth
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
Monika Abedin Sigg
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
In a previous study we established forward genetics in the choanoflagellate Salpingoeca rosetta and found that a C-type lectin gene is required for rosette development (Levin et al., 2014). Here we report on critical improvements to genetic screens in S. rosetta while also investigating the genetic basis for rosette defect mutants in which single cells fail to develop into orderly rosettes and instead aggregate promiscuously into amorphous clumps of cells. Two of the mutants, Jumble and Couscous, mapped to lesions in genes encoding two different predicted glycosyltransferases and displayed aberrant glycosylation patterns in the basal extracellular matrix (ECM). In animals, glycosyltransferases sculpt the polysaccharide-rich ECM, regulate integrin and cadherin activity, and, when disrupted, contribute to tumorigenesis. The finding that predicted glycosyltransferases promote proper rosette development and prevent cell aggregation in S. rosetta suggests a pre-metazoan role for glycosyltransferases in regulating development and preventing abnormal tumor-like multicellularity.
