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Ajin Mandaokar / Washington State University
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The paper:
B. Thines et al., "JAZ repressor proteins are targets of the
SCFCOI1 complex during jasmonate signaling," Nature, 448:
661-8, 2007. (Cited in 81 papers)
The finding:
John Browse of Washington State University and colleagues
used transcript profiling and deletion constructs to identify the
JAZ proteins, which repress jasmonates—plant hormones that
orchestrate reproductive development and trigger defensive
chemical responses to insects and bacteria in Arabidopsis.
They also showed that, in order for developmental and defensive
signaling to occur, an active form of jasmonate triggers
another protein complex—SCFCOI1—to break down the JAZ
proteins. With the suppressor proteins degraded, transcription
of jasmonate-responsive genes can proceed.
The impact:
"It made a lot of the genetics fall into place," says plant biologist
Johnathan Napier of Rothamsted Research in Harpenden, UK.
The parallels to auxin, another plant hormone, "give insight into
conserved mechanisms that plants use for signaling and regulation
of gene expression."
Other factors:
Another paper by Roberto Solano's team at the National Center
for Biotechnology in Madrid, Spain, found that JAZ repressed a
transcription factor that may also be a key player in activating
the jasmonate signaling cascade. But, the teams still don't know
which domains on JAZ proteins bind to SCFCOI1.
The next step:
Ning Zheng, a biochemist at the University of Washington,
has almost finished crystallizing the jasmonate SCFCOI1-JAZ
complex. "By solving the structure, we'll be able to tell right away
which [domain] directly interacts with SCFCOI1," says Zheng.
| Increase in JAZ transcript induction for wild-type plants treated with jasmonate: |
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In stamens: 6-40 fold |
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In 7-day-old seedling: 8-60 fold |
