Histone H1 is an evolutionarily conserved ‘linker’ histone protein which serves the important dynamic function of arranging and stabilizing chromatin structure. The mechanism by which histone H1 carries out its function remains unclear. One thing that is certain is the common use of fluorophore-tagged histone H1 protein in microscopy to track nuclei within cells. In time-lapse analyses, we observed stochastic exchange of photo-activated Dendra2-Histone-H1 protein between nuclei. We also observed heterogeneous mixing of histone proteins between nuclei in hyphae and conidiophores derived from heterokaryon fusions of histone H1-RFP and H1-GFP strains. Subsequent analysis of the resulting conidia that contained both RFP- and GFP-labeled histone H1 proteins, showed only parental genotypes. These data together suggest the stochastic exchange of histone H1 protein between nuclei is likely a result of diffusion rather than genetic recombination during karyogamy.
Full conference title:
- Asperfest 14 (2017)