Molecular cloning of a C-type lectin superfamily protein differentially expressed by CD8alpha(-) splenic dendritic cells.
Dendritic cells (DC) are potent antigen presenting cells that activate naive T cells. It is becoming increasingly clear that DC are not a homogeneous cell population, but comprise different subpopulations that differ in ontogeny and function. To further the molecular characterisation of DC, we screened for genes that were differentially expressed amongst DC subsets and could therefore give insight into their varying biological functions. Using Representational Difference Analysis (RDA) we identified a gene (CIRE) that is expressed at higher levels in the myeloid-related CD8alpha(-) DC than in the lymphoid-related CD8alpha(+) DC. CIRE is a 238 amino acid type II membrane protein, of approximately 33 kDa in size, whose extracellular region contains a C-type lectin domain. Northern blot analysis revealed that CIRE is almost exclusively expressed in DC and was not detected in organs such as heart, brain, kidney, liver, and thymus. T cells failed to express message for CIRE, whilst B cells expressed very low levels. These data here further substantiated by Northern blot analysis of 18 cell lines of various origins (myeloid, macrophage, B and T cell) where only one cell line, which was of myeloid origin and could give rise to DC, expressed mRNA for CIRE. Semi-quantitative RT-PCR suggested that CIRE is down-regulated upon activation. CIRE shares 57% identity with human DC-SIGN, a molecule that has been shown to be the ligand of ICAM-3 and that is also a receptor that binds HIV and facilitates trans-infection of T cells.
Caminschi
I
I
The Walter and Eliza Hall Institute of Medical Research, PO Royal Melbourne Hospital, Victoria 3050, Melbourne, Australia. caminschi@wehi.edu.au
Lucas
K M
KM
O'Keeffe
M A
MA
Hochrein
H
H
Laâbi
Y
Y
Brodnicki
T C
TC
Lew
A M
AM
Shortman
K
K
Wright
M D
MD
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016827:CD8 Antigens; D016466:CHO Cells; D015815:Cell Adhesion Molecules; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary; D003713:Dendritic Cells / Q000378:metabolism*; D015536:Down-Regulation; D015870:Gene Expression; D037102:Lectins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D037181:Lectins, C-Type; D008565:Membrane Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D011956:Receptors, Cell Surface / Q000145:classification / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013154:Spleen / Q000166:cytology; D015533:Transcriptional Activation; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
D016827:CD8 Antigens; D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; D037102:Lectins; D037181:Lectins, C-Type; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin; C433029:CLEC4M protein, human