Biology Reference
In-Depth Information
Table 4.
(Continued)
Notch signaling
pathway
39
0
0
1
0
Phosphatidylinositol
signaling system
77
0
1
0
0
TGF-beta signaling
pathway
70
1
1
11
0
VEGF signaling
pathway
68
3
0
5
2
Wnt signaling pathway
138
0
1
12
2
Signaling Molecules and
Interaction
Cell adhesion
molecules (CAMs)
123
2
3
2
Cytokine-cytokine
receptor interaction
242
0
3
2
ECM-receptor
interaction
85
1
3
2
Neuroactive ligand-
receptor interaction
275
1
1
0
* Cellular pathways with at least fi ve times the expected number of genes (calculated from the library composition).
Ten genes up-regulated in both tissues by wild-type PRV infection segregated into
known pathways. Most of them are involved in multiple pathways, such as
SPP1
in the
immune response pathway, the ECM-receptor interaction and focal adhesion pathway,
and
FOS
and
CDC42
in the T cell receptor signaling pathway and MAPK signaling
pathway. Moreover, it is also interesting to note that a few genes such as
SERPINE1
and
LCP2
respond differently in the two tissues studied, and while some of the path-
ways responding to the infection are ubiquitous, others appear to be tissue specifi c.
qRT-PCR Analysis for Validation of Microarray Results
In order to verify the data obtained in the microarray experiment, we confirmed the
expression profile of five selected genes with different patterns of expression:
LY96
is
differentially expressed in the same direction in both tissues;
SERPINE1
is down-reg-
ulated in the brain but up-regulated in the lungs after infection;
CDC42
and
AKT1
are
significantly up-regulated in lung tissue only, and
PIK3R1
is not significantly differen-
tially expressed. Results from qRT-PCR confirmed the direction of expression (up- or
down-regulated) obtained by microarray analysis in the five genes tested (Table 1).
The magnitude of the fold change is not the same. This is most probably due to the fact
that the array analysis is based on a cross-species hybridization whereas the RT-PCR
has been performed using species homologous primers. It is likely that the RT-PCR
analysis reflects more accurately the fold change in expression.
DISCUSSION
The virus replication cycle involves a series of host-virus interactive processes causing
changes in expression of cellular genes, and an infected host activates both innate and
adaptive immune responses to eliminate the invading virus [17]. The pig is an ideal
