Molecular cloning of the MCP-3 chemokine gene and regulation of its expression.
We have isolated a cDNA (NC28) transcribed from a mRNA which is transiently induced in U937 promonocytic cells by PMA and super-induced by cycloheximide. NC28 cDNA encodes a new member of the chemokine family, MCP-3, recently purified from MG-63 osteosarcoma cells by Van Damme et al. [1]. The MCP-3 protein sequence shows 74% identity with human monocyte chemoattractant protein 1 (MCP-1) and, like MCP-1, recombinant MCP-3 protein shows chemotactic activity for monocytes but not for neutrophils. However the secreted MCP-3 protein differs from MCP-1 in being N-glycosylated. The 3' noncoding regions of MCP-3 and MCP-1 mRNAs are more diverged (44%), allowing specific cDNA probes to be made, and indicating that the two genes are evolutionarily distant. Sequence comparisons of the 3' noncoding regions suggest that MCP-3 may be the human homologue of the mouse MARC gene [2], and that MCP-1 and MCP-3 genes arose by a gene duplication event before the mammalian radiation. Both MCP-1 and MCP-3 mRNAs are expressed by PBMC, principally by monocytes, with MCP-1 mRNA being expressed at levels 2-4 times that of MCP-3 mRNA. However, while MCP-1 mRNA is also expressed at high levels in fibroblast or astrocytoma cell lines after IL-1 and TNF stimulation, MCP-3 mRNA is expressed only at very low levels in these cells. The cellular origin of MCP-3 is thus more restricted than that of MCP-1. In our experiments on PBMC, LPS is not a consistent inducer of MCP-1 and MCP-3 mRNAs. In some experiments, it actually decreases levels of these two mRNAs, while concomitantly increasing IL-6 and TNF-alpha mRNA levels. Levels of MCP-1 and MCP-3 mRNAs in PBMC are both increased by IFN-gamma, although IL-6 mRNA is not induced. They are also increased by PHA-P and are decreased, in most cases, by IL-13 [3]. MCP-1 and MCP-3 mRNAs are thus co-ordinately regulated in monocytes in response to a number of inducing or inhibitory agents, in a manner differing in several respects from that of other monokines such as IL-6.
Minty
A
A
Sanofi Elf Bio Recherches, Labège, France.
Chalon
P
P
Guillemot
J C
JC
Kaghad
M
M
Liauzun
P
P
Magazin
M
M
Miloux
B
B
Minty
C
C
Ramond
P
P
Vita
N
N
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D002478:Cells, Cultured; D054410:Chemokine CCL7; D002630:Chemotactic Factors / Q000235:genetics*; D003001:Cloning, Molecular; D016207:Cytokines; D004247:DNA / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D018945:Monocyte Chemoattractant Proteins; D009000:Monocytes / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
C515450:CCL7 protein, human; C515451:Ccl7 protein, mouse; C515452:Ccl7 protein, rat; D054410:Chemokine CCL7; D002630:Chemotactic Factors; D016207:Cytokines; D018945:Monocyte Chemoattractant Proteins; D012333:RNA, Messenger; D004247:DNA