ABSTRACT
Our knowledge of cell biology of eukaryotes has been gained largely through studies of plant and animal cells that contain a single nucleus per cell. With the exception of unicellular yeast fungi, the majority of fungi composed of hypha contain several nuclei per hyphal compartment. A common method of visualizing nuclei in hyphae is the use of DNA-speciœc dyes (Figure 2.1). In the past few years the Neurospora chromosomal protein histone H1 gene was tagged with a gene from a jellyœsh that encodes a green šuorescent protein (GFP) that glows bright green. Several œlamentous fungi have been transformed by histone H1-GFP, and the tagged nuclei are visualized using a šuorescence microscope under blue-light excitation (488 mm) (see book cover). This enables the study of nuclear dynamics in living hyphae by video microscopy. Combined with the ease of isolating mutants in fungi and the availability of genome sequences of some species, this has stimulated studies of conditions that inšuence mitosis, the identiœcation of nuclear genes involved in nuclear movement, their distribution in hypha, and morphogenesis. The feasibility of fusing fungal cells containing two different nuclear types into heterokaryon makes has made it possible to study cooperation or competition between nuclei when put in a common cytoplasm of fungal compartment.
