title: Clustered nuclei maintain autonomy and nucleocytoplasmic ratio control in a syncytium.
abstract: Nuclei in syncytia found in fungi, muscles, and tumors can behave independently despite cytoplasmic translation and the homogenizing potential of diffusion. We use a dynactin mutant strain of the multinucleate fungus Ashbya gossypii with highly clustered nuclei to assess the relative contributions of nucleus and cytoplasm to nuclear autonomy. Remarkably, clustered nuclei maintain cell cycle and transcriptional autonomy; therefore some sources of nuclear independence function even with minimal cytosol insulating nuclei. In both nuclear clusters and among evenly spaced nuclei, a nucleus' transcriptional activity dictates local cytoplasmic contents, as assessed by the localization of several cyclin mRNAs. Thus nuclear activity is a central determinant of the local cytoplasm in syncytia. Of note, we found that the number of nuclei per unit cytoplasm was identical in the mutant to that in wild-type cells, despite clustered nuclei. This work demonstrates that nuclei maintain autonomy at a submicrometer scale and simultaneously maintain a normal nucleocytoplasmic ratio across a syncytium up to the centimeter scale.
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH 03755.
authors.forename: Samantha E R
authors.initials: SE
authors.lastname: Dundon
authors.affiliation: Departments of Mathematics and Biomathematics, University of California, Los Angeles, Los Angeles, CA 90095.
authors.forename: Shyr-Shea
authors.initials: SS
authors.lastname: Chang
authors.affiliation: Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH 03755.
authors.forename: Patricia
authors.initials: P
authors.lastname: Occhipinti
authors.affiliation: Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Hari
authors.initials: H
authors.lastname: Shroff
authors.affiliation: Departments of Mathematics and Biomathematics, University of California, Los Angeles, Los Angeles, CA 90095.
authors.forename: Marcus
authors.initials: M
authors.lastname: Roper
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH 03755 The Bell Center, Marine Biological Laboratory, Woods Hole, MA 02543 Amy.Gladfelter@Dartmouth.edu.
authors.forename: Amy S
authors.initials: AS
authors.lastname: Gladfelter
mesh_terms: D002453:Cell Cycle / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism* / Q000502:physiology; D048750:Cell Nucleus Division / Q000502:physiology; D016213:Cyclins / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism / Q000473:pathology; D005656:Fungal Proteins / Q000378:metabolism; D005658:Fungi / Q000378:metabolism; D015726:Giant Cells / Q000378:metabolism* / Q000502:physiology; D008938:Mitosis; D004718:Saccharomycetales / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: D016213:Cyclins; D005656:Fungal Proteins