|
Summary of Research Projects (Supports in 2003
Fiscal Year)
| Subjects |
Genetic Analysis of Light Signal Transduction Mediated by Reactive Oxigen
Species in Neurospora crassa |
| Representative researcher |
Yokohama City University Kohji HASUNUMA |
| As an early event during
light signal transduction we have proposed nucleoside diphosphate
kinase -1 (NDK-1) will be a transducer of the signal. Upon
illumination by blue, NDK-1 showed an increase in the phosphorylation
of it. The point mutant ndk-1P72H showed sensitivity to methyl
viologen and hydrogen peroxide, as a sod-1 (super oxide dismutase)
mutant. did. These two mutants showed lack of light indeuced
perithecial polarity. Although ndk-1P72H showed reduced rate
of accumulation of carotenoid in the mycelia, sod-1 showed
accerelation of it. NDK-1 was suggested to form protein complex
with catalases, Cat-1, Cat-2 and Cat-3, which were cloned
and tried to knock out the genes. The gene for ndk-1 was
also knocked out to obtain final results concerning to the
function of NDK-1 during light signal transduction. The mutants,
ndk-1RIP-1 and ndk-1RIP-2 showed no phosphorylation activity
of NDK-1. ndk-1RIP-1 produced no mRNA for ndk-1. However,
ndk-1RIP-2 produced trancated NDK-1 protein. Both mutants
accumulated reduced amounts of carotenoid forming yellowish
mycelia. NDK-1 was strongly suggested to be a transducer
of light regulating intracellular ROS possibly by interacting
with catalases. We isolated methyl viologen resistant mutants
from wild type and ndk-1P72H. Two mutants crossed into wild
type three times were currently checked for their activity
in super oxide dismutases and catalases. |
|
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