Green fluorescent protein targeted to the nucleus, a transgenic phenotype useful for studies in plant biology

We present a characterization of transgenic Arabidopsis thaliana (L.) Heynh . plants expressing a chimeric gene comprising the Green Fluorescent Protei n (GFP) and beta-glucuronidase (GUS) coding sequences, fused to an efficien t nuclear localization signal (NLS). The transgenic plants accumulate the f usion protein in their nuclei, and this provides a novel phenotype, that of green-fluorescent nuclei. The fluorescent nuclei are readily observed usin g conventional epifluorescence and laser scanning confocal microscopy. We d escribe the use of this phenotype for in vivo studies of nuclear shape and movement, cell division, and for analysis of the transcriptional activities of constitutive and tissue-specific promoters. We propose that the phenoty pe of fluorescent nuclei will prove particularly valuable in histological, physiological and developmental studies of higher plants that require the f acile observation of nuclei within living cells and in the absence of fixat ion or external staining. (C) 1999 Annals of Botany Company.