Saskatoon, Saskatchewan, Canada
January 25, 2008
A
University of Saskatchewan team of scientists has isolated a
gene that has never before been identified in helping plants to
resist stress.
The study-published this month in the top-ranked plant journal
The Plant Cell-could pave the way for development of
agricultural and forestry crops that are more tolerant to
environmental stresses such as ultra-violet light and other
types of radiation.
"Our next step is to see if plant genes we've isolated also play
a similar role in fighting infections," said U of S
microbiologist Wei Xiao. "In previous research, our team and
others have shown that similar genes in human and animal cells
play an important role in protection against both viral and
bacterial infections."
In an unusual collaboration, Xiao teamed up with U of S
biochemist Hong Wang, two post-doctoral fellows and three
graduate students on the study. Doctoral student Rui Wen is the
lead author on the paper.
Using Arabidopsis, a widely accepted research model plant
closely related to canola, the team cloned and characterized
four genes suspected of playing a role in the plant's stress
responses. The team found that when plants were subjected to a
DNA-damaging stressor, the plants in which one of the four genes
had been turned off produced seedlings that grew slower and
often died, compared with a control group.
"This tells us that these genes likely play an important role in
maintaining the genetic stability of the plant and protecting
the plant from stress," said Xiao.
The next step is to look at whether turning on or off any of the
other three genes will affect the plant's resistance to
environmental stresses, including viral and bacterial
infections.
Xiao's previous research used cultured mammalian cells to study
cancer and immunity. But since deletion of genes in living
mammals would cause the embryos to die, the team turned to the
plant model.
"This study demonstrates for the first time that we can study
this group of genes at the whole organism level, rather than
just at the cellular level, which could have applications down
the road for human and animal medicine in fighting cancer and
infections," said Xiao, noting that plant, animal and human
studies are increasingly converging around gene-based research.
In previous research using human cells, Xiao found that human
genes similar to the four plant genes not only fight carcinogens
but play a role in fighting viral and bacterial infections.
"There are actually two closely related genes involved-one
fighting against infections and the other against cancer," said
Xiao. "The two genes-Beauty and the Beast-complement each other
when they work together, but if Beast is constantly being
expressed to stimulate cells to uncontrollably reproduce, this
situation can lead to cancer."
Xiao's discovery of the "Beauty and Beast" genes that may govern
the development of cancer is cited in Milestones in Canadian
Health Research:
http://www.cihr-irsc.gc.ca/e/35216.html
Ten years ago, Xiao discovered a gene in baker's yeast that when
inactivated causes cells to be more susceptible to DNA-damaging
agents. His team then identified two similar human genes and
found that when either of these was put into the yeast cells
containing the inactivated gene, the problem was soon fixed and
the cells grew normally.
The plant gene products under study by Xiao and Wang bind with a
protein (Ubc13) which has recently been found to control
activation of the immune response. This protein has also been
linked to an increasing number of human diseases, including
Parkinson's and breast cancer.
Long term, the team's goal is to develop screening tests for
humans and animals that could detect a cancer-causing imbalance,
allowing earlier treatment and prevention. Diagnostic antibodies
suitable for such tests have been developed by Xiao and his U of
S colleagues and have been licensed to California-based Zymed
Laboratories, Inc., and Santa Cruz Biotechnology, Inc.
The study was funded by both the Canadian Institutes of Health
Research and the Natural Sciences and Engineering Research
Council. A copy of the team's article is available upon request. |
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