Download A : When the same genes are found in each five sensory organs

Figure 5
Genes present in the five sensory organs (KUROV)
A : When the same genes are found in each five sensory organs, they are grouped in
what is called “KUROV”, where K stands for the Kölliker organ corresponding to the
sensory region of the cochlea, U for the sensory region of the utricule, R for the
sensory retina, O for the olfactory organ and V for the follicule of vibrissae.
For this analysis we have used the STRING database along with Cytoscape in order
to find the possible interactions between the 623 genes that are common to the five
sensory tissues belonging to KUROV along with KEGG data base for possible
functional pathways involved with specific genes. Out of 623 genes of KUROV, only
163 presented direct interactions as found with STRING where they can be grouped
into 7 major networks, although other less important networks were also found. The
first network is mainly composed of ribosomal proteins and mitochondrial ribosomal
proteins showing numerous interactions. This first network is linked to a second one
trough the Eif2s1 gene (Translation initiation factor2, subunit 1alpha), whose several
genes are involved in protein processing in the endoplasmic reticulum and apoptosis.
The first network is also connected to a third one trough the Rps27l gene (Ribosomal
protein S27, like) where genes are linked to several cellular processes such as focal
adhesion, cytoskeleton regulation and neural development. This third network of
genes is related to a forth one through the Aurka gene (an Aurora kinase1). In this
network several proteosome genes are present as well as other genes involved in
important cellular pathways such as cell cycle, meiosis, and Ubiquitin mediated
proteolysis. Csnk1a1 involved in Wnt signaling, and Hedgehog signaling pathways
makes the connection with the fifth network mainly made of genes involved with
tubulin, actin, centrosomal and cilia proteins.
A sixth network independent from the previous ones is made of genes mainly
involved in transcription with several spliceosome genes and transcription factors.
Another independent network, the seventh corresponds to several transcription
factors while other genes are involved in cell cycle and signaling pathways.
B: Examples of what can offer mining trough the STRING database for two genes as
illustrated by using Cytoscape. One gene from the sixth pathway of Figure 5, i.e.
Polr2g and a second one from the seventh pathway, Lmo4.
The Polr2g gene coding for a RNA polymerase was connected directly with 14 genes
present in KUROV, and indirectly toward a pool of 224 single target genes.
C: Taking one gene out of the 14 genes connected directly to the Polr2g gene like
Pole, ( a DNA polymerase), this gene presents only one direct interaction with Polr2g
and several indirect connections via 12 target genes related to purine and pyrimidine
metabolism important in DNA replication.
D: The general expression of these genes may be useful to predict their importance
during development for the five sensory organs. One example like Lmo4 from the
sixth pathway is related directly to 7 genes present in KUROV and indirectly via a
single connection to 148 outside target genes.