Murine complement receptor gene expression: Cr2 gene transcripts are depressed during a high dose microbial challenge.
The murine Cr2 gene encodes mRNA that produce two protein products predicted to be approximately 145,000 M(r) (Cr2-145) and 190,000 M(r) (Cr2-190). All cells examined which express the Cr2 gene produce transcripts encoding both the Cr2-145 and Cr2-190 proteins: both transcripts are constitutively expressed by mature B cells. To determine if Cr2 expression could be altered by activating splenic B cells, splenic cultures were incubated with lipopolysaccharide (LPS) and cell surface Ig chains were cross-linked with anti-mu. In the presence of LPS and anti-mu both Cr2 and Oct-2 transcripts were diminished while the control beta-actin transcript levels remained unchanged. However, when LPS alone was added, only the Cr2 transcript levels were diminished. To test if these findings could be reproduced in vivo, animals were provided with a peritoneal injection of either Escherichia coli or Listeria monocytogenes and transcript levels analysed. The quantities of both Cr2 transcripts, as well as those encoding Oct-2, were substantially reduced in splenocytes and peripheral lymphatic tissues obtained from these infected mice while those encoding the mouse Crry protein, the B-cell marker CD19 and beta-actin remained unchanged. These data suggest that when confronted with a major bacterial infection, murine B cells respond by shutting down synthesis of transcripts encoding the Cr2 and Oct-2 gene products.
Department of Pathology, University of Utah School of Medicine, Salt Lake City 84132.
S S
SS
Tan
E M
EM
O'Toole
C B
CB
Kurtz
J H
JH
Weis
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001424:Bacterial Infections / Q000276:immunology*; D001483:Base Sequence; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D015870:Gene Expression / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008221:Lymphoid Tissue / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D050813:Octamer Transcription Factor-2; D012333:RNA, Messenger / Q000378:metabolism*; D011951:Receptors, Complement / Q000235:genetics*; D017464:Receptors, Complement 3d / Q000378:metabolism*; D013154:Spleen / Q000276:immunology; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000276:immunology
D004268:DNA-Binding Proteins; D008070:Lipopolysaccharides; D050813:Octamer Transcription Factor-2; C489206:Pou2f2 protein, mouse; D012333:RNA, Messenger; D011951:Receptors, Complement; D017464:Receptors, Complement 3d; D014157:Transcription Factors