The immediate early genes of human cytomegalovirus require only proximal promoter elements to upregulate expression of interleukin-1 beta.
Human cytomegalovirus (HCMV) can infect monocytes and macrophages. The immediate early one (IE1) gene product of HCMV positively regulates its own expression, as well as the expression of the interleukin-1 beta (IL-1) gene. This study describes the IL-1 promoter proximal region required for upregulation of IL-1 gene expression by the HCMV IE1 or IE1 plus IE2 gene products. An IL-1 chloramphenicol acetyltransferase (CAT) construct containing the IL-1 genomic upstream sequence from position -1097 to +14 and four additional IL-1CAT plasmids containing progressive deletions of the -1097 to -131 sequence were used to evaluate the effect of the HCMV IE gene products on IL-1 gene expression. IL-1CAT plasmids were transfected into a monocytic cell line, THP-1, with plasmids containing either the IE promoter-regulatory region upstream of the bona fide IE1 (pIE1), IE2 (pIE2), or IE1+2 genes (pIE1+2) or a control plasmid containing the IE promoter-regulatory region alone (pLink760). In the presence of pIE1+2, there was an approximate 15-fold increase in CAT activity compared with the control, pLink760, in cells with CAT plasmids containing the -1097 to +14 IL-1 sequence. Plasmids with progressive deletions of this sequence, including the plasmid containing the shortest upstream segment (-131 to +14) also had an approximate 15-fold increase in CAT activity. The upregulation of IL-1 expression was mediated, primarily, by IE1 and not by IE2. This effect was promoter specific because an IL-1CAT plasmid with a complete deletion of the proximal promoter elements (-234 to +146) did not respond to the HCMV IE gene products.(ABSTRACT TRUNCATED AT 250 WORDS)
Crump
J W
JW
Department of Internal Medicine, Veterans Affairs, Iowa City, Iowa.
Geist
L J
LJ
Auron
P E
PE
Webb
A C
AC
Stinski
M F
MF
Hunninghake
G W
GW
D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism*; D003587:Cytomegalovirus / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D015967:Gene Expression Regulation, Viral / Q000235:genetics*; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic; D015854:Up-Regulation
D007375:Interleukin-1; D015500:Chloramphenicol O-Acetyltransferase