TY - JOUR
T1 - Molecular cloning and cellular localization of the scavenger receptor SCARF1 in common carp
AU - Østergaard, A.E.
AU - Fink, I.R.
AU - Sukinta, A.
AU - Yixian, L.
AU - Forlenza, M.
AU - Wiegertjes, G.F.
PY - 2013
Y1 - 2013
N2 - The recognition of pathogens by the innate immune system relies on a
wide range of germ-line encoded pattern recognition receptors of which
some belong to the large superfamily of scavenger receptors (SRs). These
receptors are expressed on cells surveying potential portals of entry,
including macrophages, dendritic cells and endothelial cells and are
involved in recognition of both endogenous and pathogen-derived ligands.
Here we describe for the first time an evolutionarily conserved member of
the SR family, named scavenger receptor class F-member1 (SCARF1), in the
common carp (Cyprinus carpio). Orthologs of mammalian SCARF1 have
been reported in nematodes and shown to be involved in recognition of
e.g. beta-glucans. Also, SCARF1 has been shown to mediate an inflammatory
cytokine response upon ligand binding whilst functioning as co-receptor
for Toll-like receptors (TLRs).
We found two SCARF1 genes in the common carp genome, confirming the
hypothesis that carp has undergone an extra genome duplication event
compared to zebrafish, where only one SCARF1 gene is found. The two
SCARF1 genes in carp are 94% similar and show comparable mRNA
expression levels. Sequence analysis of SCARF1 reveals a high level of
amino acid conservation compared to the human orthologue. Phylogenetic
analysis of carp SCARF1 with other vertebrate SCARF1 genes groups carp
and zebrafish together with high bootstrap values. Synteny studies show
conserved linkage with several neighbouring genes when comparing
genomic regions from different species. Gene expression analysis of
SCARF1 shows expression in several organs, whereas gene expression
analysis of purified cell populations shows highest expression in endothelial
cells, but also macrophages, granulocytes, thrombocytes and thymocytes
show SCARF1 gene expression. In contrast, no expression was
observed in B cells. Previously, our group has cloned TLR2 from common
carp and we are now investigating the possible role of SCARF1 acting as an
internalizing receptor that would facilitate TLR activation upon phagocytosis
of ligands. The localization of SCARF1 was studied by confocal microscopy
of human (HEK293) and fish (EPC) cell lines transfected with a
fluorescently tagged receptor. In addition, antibodies directed against a
V5-tagged version of SCARF1 were also used to detect SCARF1 localization.
These studies showed that carp SCARF1 is expressed in the cytoplasm, but
also on the cell membrane, which is comparable to human SCARF1 localization.
We are performing phagocytosis studies in order to verify the
internalizing ability of SCARF1 and its potential role in TLR signaling.
AB - The recognition of pathogens by the innate immune system relies on a
wide range of germ-line encoded pattern recognition receptors of which
some belong to the large superfamily of scavenger receptors (SRs). These
receptors are expressed on cells surveying potential portals of entry,
including macrophages, dendritic cells and endothelial cells and are
involved in recognition of both endogenous and pathogen-derived ligands.
Here we describe for the first time an evolutionarily conserved member of
the SR family, named scavenger receptor class F-member1 (SCARF1), in the
common carp (Cyprinus carpio). Orthologs of mammalian SCARF1 have
been reported in nematodes and shown to be involved in recognition of
e.g. beta-glucans. Also, SCARF1 has been shown to mediate an inflammatory
cytokine response upon ligand binding whilst functioning as co-receptor
for Toll-like receptors (TLRs).
We found two SCARF1 genes in the common carp genome, confirming the
hypothesis that carp has undergone an extra genome duplication event
compared to zebrafish, where only one SCARF1 gene is found. The two
SCARF1 genes in carp are 94% similar and show comparable mRNA
expression levels. Sequence analysis of SCARF1 reveals a high level of
amino acid conservation compared to the human orthologue. Phylogenetic
analysis of carp SCARF1 with other vertebrate SCARF1 genes groups carp
and zebrafish together with high bootstrap values. Synteny studies show
conserved linkage with several neighbouring genes when comparing
genomic regions from different species. Gene expression analysis of
SCARF1 shows expression in several organs, whereas gene expression
analysis of purified cell populations shows highest expression in endothelial
cells, but also macrophages, granulocytes, thrombocytes and thymocytes
show SCARF1 gene expression. In contrast, no expression was
observed in B cells. Previously, our group has cloned TLR2 from common
carp and we are now investigating the possible role of SCARF1 acting as an
internalizing receptor that would facilitate TLR activation upon phagocytosis
of ligands. The localization of SCARF1 was studied by confocal microscopy
of human (HEK293) and fish (EPC) cell lines transfected with a
fluorescently tagged receptor. In addition, antibodies directed against a
V5-tagged version of SCARF1 were also used to detect SCARF1 localization.
These studies showed that carp SCARF1 is expressed in the cytoplasm, but
also on the cell membrane, which is comparable to human SCARF1 localization.
We are performing phagocytosis studies in order to verify the
internalizing ability of SCARF1 and its potential role in TLR signaling.
U2 - 10.1016/j.fsi.2013.03.278
DO - 10.1016/j.fsi.2013.03.278
M3 - Abstract
SN - 1050-4648
VL - 34
SP - 1727
EP - 1727
JO - Fish and Shellfish Immunology
JF - Fish and Shellfish Immunology
IS - 6
ER -