ENETIC tumors in Nicotiana species hybrids have been reported by several Ginvestigators. These tumors are formed in certain specific hybrid combinations on stems, roots, and occasionally on leaves of all or part of the F, progeny. Since the discovery by KOSTOFF (1930) of nine interspecific tumorous hybrids, almost 20 additional hybrid combinations have been reported in which the entire progeny ...

The genetic transformation of the higher plant Nicotiana plumbaginifolia to express the protein apoaequorin has recently been used as a method to measure cytosolic free calcium ([Ca2+]i) changes within intact living plants (Knight, M. R., A. K. Campbell, S. M. Smith, and A. J. Trewavas. 1991. Nature (Lond.). 352:524-526; Knight, M. R., S. M. Smith, and A. J. Trewavas. 1992. Proc. Natl. Acad. Sc...

The structural determinants involved in the targeting of multitransmembrane-span proteins to the plasma membrane (PM) remain poorly understood. The plasma membrane H+ -ATPase (PMA) from Nicotiana plumbaginifolia, a well-characterized 10 transmembrane-span enzyme, was used as a model to identify structural elements essential for targeting to the PM. When PMA2 and PMA4, representatives of the two...

Induction of double strand breaks (DSBs) is coupled to meiotic and mitotic recombination in yeast. We show that also in a higher eukaryote induction of DSBs is directly correlated with a strong enhancement of recombination frequencies. We cotransfected Nicotiana plumbaginifolia protoplasts with a plasmid carrying a synthetic I-SceI gene, coding for a highly sequence specific endonuclease, toget...

Tobacco (Nicotiana plumbaginifolia) seedlings genetically transformed to express apoaequorin were incubated in h-coelenterazine to reconstitute the calcium-sensitive luminescent protein aequorin. Treatment of these seedlings with hydrogen peroxide resulted in a transient burst of calcium-dependent luminescence lasting several minutes. Even though the hydrogen peroxide stimulus was persistent, t...

The committed step in the biosynthesis of the phytochrome chromophore phytochromobilin involves the oxidative cleavage of heme by a heme oxygenase (HO) to form biliverdin IXalpha. Through positional cloning of the photomorphogenic mutant hy1, the Arabidopsis HO (designated AtHO1) responsible for much of phytochromobilin synthesis recently was identified. Using the AtHO1 sequence, we identified ...

U-snRNA genes in higher plants contain two essential promoter elements, the USE with sequence RTCCCACATCG and the TATA-like box, positioned in the -70 and -30 regions, respectively. Using an oligodeoxynucleotide containing the USE motif and oligodeoxynucleotides specific for the intragenic regions conserved in U-snRNAs, several sequences encoding U6 and U3 snRNAs were determined by polymerase c...

The plasma membrane H(+)-ATPase builds up a pH and potential gradient across the plasma membrane, thus activating a series of secondary ion and metabolite transporters. pma4 (for plasma membrane H(+)-ATPase 4), the most widely expressed H(+)-ATPase isogene in Nicotiana plumbaginifolia, was overexpressed in tobacco. Plants that overexpressed PMA4 showed no major changes in plant growth under nor...