Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.1.26.4 (
RNase H
)
2,751
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Intercellular adhesion molecule 1
(
ICAM-1
) is a glycoprotein expressed on the surface of both hemopoietic and nonhemopoietic cells that mediates, in part, the emigration of leukocytes out of the vasculature. Expression of
ICAM-1
on the surface of human umbilical vein endothelial cells and a human lung carcinoma cell line (A549) was increased by interleukin-1 beta, tumor necrosis factor alpha, and interferon gamma in a concentration-dependent manner. Phosphorothioate antisense oligonucleotides designed to hybridize to 10 target sites on the human ICAM-1 mRNA were tested for inhibition of
ICAM-1
expression in both cell lines by an
ICAM-1
enzyme-linked immunosorbent assay. Based upon potency and unique mRNA target sites, two oligonucleotides were studied in greater detail: ISIS 1570, which targeted the AUG translation initiation codon, and ISIS 1939, which targeted specific sequences in the 3'-untranslated region of the mRNA. Both oligonucleotides specifically inhibit expression of
ICAM-1
as analyzed by immunoprecipitation of 35S-labeled proteins. Treatment of cells with ISIS 1939 promoted a reduction in ICAM-1 mRNA, whereas ISIS 1570 did not change the level of ICAM-1 mRNA, suggesting that the two oligonucleotides may be inhibiting
ICAM-1
expression by two different mechanisms. The activity of both oligonucleotides was blocked by hybridization of the oligonucleotide to its complementary sense strand prior to addition to the cells. Neither ISIS 1570 nor ISIS 1939 changed the transcriptional rate of the
ICAM-1
gene, demonstrating that both oligonucleotides were working through a post-transcriptional mechanism. 2'-O-Methyl phosphorothioate analogs, which do not support
RNase H
-mediated cleavage of target mRNA, were used to determine if the active antisense oligonucleotides inhibited
ICAM-1
expression by an
RNase H
-dependent mechanism. The 2'-O-methyl phosphorothioate analog of ISIS 1939 did not significantly reduce interleukin-1 beta-induced
ICAM-1
expression, whereas the 2'-O-methyl phosphorothioate analog of ISIS 1570 did inhibit
ICAM-1
expression, suggesting that the reduction of ICAM-1 mRNA following treatment with ISIS 1939 was due, in part, to
RNase H
-mediated hydrolysis. Adherence of HL-60 cells to human umbilical vein cell monolayers was inhibited by ISIS 1570 and ISIS 1939, demonstrating that the reduced levels of
ICAM-1
impact on
ICAM-1
-associated function.
...
PMID:Antisense oligonucleotides inhibit intercellular adhesion molecule 1 expression by two distinct mechanisms. 168 Aug 58
Little is known about the mechanisms that account for inhibition of gene expression by antisense oligonucleotides at the level of molecular cell biology. For this purpose, we have selected potent 2'-O-(2-methoxy)ethyl antisense oligonucleotides (IC50 = 2 and 6 nM) that target the 5' cap region of the human
intercellular adhesion molecule 1
(
ICAM-1
) transcript to determine their effects upon individual processes of mRNA metabolism in HUVECs. Given the functions of the 5' cap structure throughout mRNA metabolism, antisense oligonucleotides that target the 5' cap region of a target transcript have the potential to modulate one or more metabolic stages of the message inside the cell. In this study we found that inhibition of protein expression by these
RNase H
independent antisense oligonucleotides was not due to effects on splicing or transport of the
ICAM-1
transcript, but due instead to selective interference with the formation of the 80 S translation initiation complex. Interestingly, these antisense oligonucleotides also caused an increase in ICAM-1 mRNA abundance in the cytoplasm. These results imply that ICAM-1 mRNA turnover is coupled in part to translation.
...
PMID:2'-O-(2-Methoxy)ethyl-modified anti-intercellular adhesion molecule 1 (ICAM-1) oligonucleotides selectively increase the ICAM-1 mRNA level and inhibit formation of the ICAM-1 translation initiation complex in human umbilical vein endothelial cells. 911 64
