Biology Reference
In-Depth Information
Figure 4.3
Proposed model for the influence of the intracellular iron concentration and
the presence of reactive oxygen species (ROS) in FurA activity. See the colour plate.
Erdmann, & Hagemann, 2003
;
Nakamura, Kaneko, Miyajima, & Tabata,
1999
), whose phenotypes together with the high sequence homology
between Sll0567 and FurA (81%) indicates that both
all1691
and
sll0567
genes are orthologues.
3.1.2.2. PerR and the oxidative stress response
Inactivation of the
Synechocystis
PCC 6803
slr1738
gene and functional
genomics of the resulting disruption mutant under different stress condi-
tions (
Li, Singh, McIntyre, & Sherman, 2004
;
Singh, Li, & Sherman, 2004
)
clearly point to this gene as a
perR
orthologue that is involved in the control
of the peroxide stress response in this unicellular cyanobacteria. Induction
of Slr1738 by H
2
O
2
and the higher tolerance of the Δ
slr1738
mutant to
peroxide and paraquat consistent with the increased expression of several
antioxidant genes also support those results (
Houot et al., 2007
).
A comparison of differentially regulated genes of the peroxide stimulon
in
Synechocystis
PCC 6803 and in the Δ
perR
mutant strain allowed identify-
ing a novel type 2 peroxiredoxin gene, namely
sll1621
, as a main PerR tar-
get. The PerR regulon (
Table 4.2
) also includes some genes related to iron
homeostasis, such as
idiA
and
mrgA
(
Li et al., 2004
). Moreover, the exposure
to methyl viologen under normal or high light allowed the identification