PMID- 8764042
OWN - NLM
STAT- MEDLINE
DCOM- 19961107
LR  - 20200724
IS  - 0022-538X (Print)
IS  - 1098-5514 (Electronic)
IS  - 0022-538X (Linking)
VI  - 70
IP  - 8
DP  - 1996 Aug
TI  - Two distinct upstream regulatory domains containing multicopy cellular 
      transcription factor binding sites provide basal repression and inducible 
      enhancer characteristics to the immediate-early IES (US3) promoter from human 
      cytomegalovirus.
PG  - 5312-28
AB  - The US3 gene of human cytomegalovirus (HCMV) is expressed at immediate-early (IE) 
      times in permissive HF cells, but not in nonpermissive rodent cells, and encodes 
      several proteins that have been reported to have regulatory characteristics, 
      although they are dispensable for growth in cell culture. Both spliced and 
      unspliced forms of US3 IE transcripts are associated with the second of only two 
      known large and complex upstream enhancer domains within the 229-kb HCMV genome, 
      which we refer to as the IES cis-acting control region. Only the 260-bp proximal 
      segment (from -313 to -55) of the 600-bp IES control domain, which contains 
      multicopy NF-kappaB binding sites, proved to be necessary to transfer both high 
      basal expression plus phorbol ester- and okadaic acid-inducible characteristics 
      to heterologous promoters in transient assays in U-937 and K-562 cells. However, 
      the IES control region contains a distinctive 280-bp distal domain, characterized 
      by the presence of seven interspersed repeats of a 10-bp TGTCGCGACA palindromic 
      consensus motif that encompasses a NruI site. This far upstream Nru repeat region 
      (from -596 to -314) imparted up to 20-fold down-regulation effects onto strong 
      basal heterologous promoters as well as onto the IES enhancer plus minimal 
      promoter region in both U-937 and K-562 cells. Functional Nru repressor elements 
      (NREs) could not be generated by multimerizing either the palindromic (P) Nru 
      motifs alone or adjacent degenerate interrupted (I Nru motifs alone. However, 
      multimerized forms of the combined P plus I elements reconstituted the full 
      20-fold cis-acting down-regulation phenotype of the intact NRE domain. The P and 
      I forms of the Nru elements each bound independently and specifically to related 
      cellular DNA-binding factors to form differently migrating A or B complexes, 
      respectively, whereas the combined P plus I elements bound cooperatively to both 
      the A and B complexes with high affinity. Interestingly, nuclear extracts from 
      U-937, K-562, HeLa, and Vero cells all formed both the A and B NRE binding factor 
      complexes, whereas those from HF cells produced only A complexes, and Raji, HL60, 
      and BALB/c 3T3 cells lacked both types of binding factor complexes. The core 
      pentameric CGACA and CGATA half sites present in both the P and I Nru motifs are 
      related to recently described Drosophila chromosomal insulator binding sites. 
      Therefore, in addition to its cis-repression or silencer characteristics, the NRE 
      domain appears likely to act to shield adjacent segments of the viral genome from 
      the chromatin-reorganizing effects of the IES-inducible enhancer. We speculate 
      that differential expression and regulation of the IES enhancer-controlled US3 
      protein, either in concert with or separately from the major IE (MIE) 
      enhancer-controlled IE1 and IE2 transactivator proteins, may play a critical role 
      in determining HCMV permissiveness in some cell types and perhaps also in the 
      establishment of or reactivation from latency.
FAU - Chan, Y J
AU  - Chan YJ
AD  - The Molecular Virology Laboratories, Department of Pharmacology, Johns Hopkins 
      University School of Medicine, Baltimore, Maryland 21205, USA.
FAU - Tseng, W P
AU  - Tseng WP
FAU - Hayward, G S
AU  - Hayward GS
LA  - eng
GR  - NIH 5T32-M07626/PHS HHS/United States
GR  - R01-AI31454/AI/NIAID NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Virol
JT  - Journal of virology
JID - 0113724
RN  - 0 (NF-kappa B)
SB  - IM
MH  - Animals
MH  - Base Sequence
MH  - Binding Sites
MH  - Cell Line
MH  - Cytomegalovirus/*genetics
MH  - Enhancer Elements, Genetic/*genetics
MH  - *Gene Expression Regulation, Viral
MH  - *Genes, Immediate-Early
MH  - Humans
MH  - Molecular Sequence Data
MH  - Mutation
MH  - NF-kappa B/*genetics
MH  - Promoter Regions, Genetic/*genetics
MH  - Virus Integration
PMC - PMC190489
EDAT- 1996/08/01 00:00
MHDA- 1996/08/01 00:01
PMCR- 1996/08/01
CRDT- 1996/08/01 00:00
PHST- 1996/08/01 00:00 [pubmed]
PHST- 1996/08/01 00:01 [medline]
PHST- 1996/08/01 00:00 [entrez]
PHST- 1996/08/01 00:00 [pmc-release]
AID - 10.1128/JVI.70.8.5312-5328.1996 [doi]
PST - ppublish
SO  - J Virol. 1996 Aug;70(8):5312-28. doi: 10.1128/JVI.70.8.5312-5328.1996.