ABSTRACT & LINKS
Bass H.W., Nagar S., Hanley-Bowdoin L., and Robertson D. (2000).
Chromosome condensation induced by geminivirus infection of mature plant
cells. Journal Cell Science 113(7):1149-1160.
Large JPG of cover Photo
The geminivirus, tomato golden mosaic virus (TGMV), replicates
its single-stranded DNA genome through double-stranded DNA
intermediates in nuclei of differentiated plant cells using host replication
machinery. We analyzed the distribution of viral and plant DNA in
nuclei of infected leaves using fluorescence in situ hybridization (FISH).
TGMV-infected nuclei showed up to a six-fold increase in total volume
and displayed a variety of viral DNA accumulation patterns. The most
striking viral DNA patterns were bright, discrete intranuclear
compartments, but diffuse nuclear localization was also observed.
Quantitative and spatial measurements revealed that these
compartments accounted for 1 - 18% of the total nuclear volume or 2 -
45% of the total nuclear FISH signals. In contrast, plant DNA was
concentrated around the nuclear periphery. In a significant number of
nuclei, the peripheral chromatin was organized as condensed prophase-
like fibers. A combination of FISH analysis and indirect
immunofluorescence with viral coat protein antibodies revealed that
TGMV virions are associated with the viral DNA compartments.
However, the coat protein antibodies failed to cross react with some
large viral DNA inclusions, suggesting that encapsidation may occur
after significant viral DNA accumulation. Infection by a TGMV mutant
with a defective coat protein open reading frame resulted in fewer and
smaller viral DNA-containing compartments, possibly because single-
stranded DNA was not stabilized in virions. Nuclei infected with the
mutant virus increased in size and in some cases showed chromosome
condensation. Together, these results established that geminivirus
infection alters nuclear architecture and can induce plant chromatin
condensation characteristic of cells arrested in early mitosis.
back to pubs page