MicroRNAs are predicted to regulate approximately 30% of all human genes by targeting sequences in their 3' UTR. Polymorphisms in 3' UTR of several genes have been reported to affect gene expression, but the mechanism is not fully understood. Here, we demonstrate that 829C-->T, a naturally occurring SNP, near the miR-24 binding site in the 3' UTR of human dihydrofolate reductase (DHFR) affects DHFR expression by interfering with miR-24 function, resulting in DHFR overexpression and methotrexate resistance. miR-24 has a conserved binding site in DHFR 3' UTR. DHFR with WT and 3' UTR containing the 829C-->T mutation were expressed in DG44 cells that lack DHFR. Overexpression of miR-24 in cells with WT DHFR resulted in down-regulation of DHFR protein, whereas no effect on DHFR protein expression was observed in the mutant 3' UTR-expressing cells. Inhibition of endogenous miR-24 with a specific inhibitor led to up-regulation of DHFR in WT and not in mutant cells. Cells with the mutant 3' UTR had a 2-fold increase in DHFR mRNA half-life, expressed higher DHFR mRNA and DHFR protein, and were 4-fold more resistant to methotrexate as compared with WT cells. SNP-829C-->T, therefore, leads to a decrease in microRNA binding leading to overexpression of its target and results in resistance to methotrexate. We demonstrate that a naturally occurring miRSNP (a SNP located at or near a microRNA binding site in 3' UTR of the target gene or in a microRNA) is associated with enzyme overproduction and drug resistance.
Pharmacology, Toxicology and Pharmaceutical Science
7
4%
Immunology and Microbiology
3
2%
Other
7
4%
Unknown
29
16%
Attention Score in Context
Attention Score in Context
This research output has an Altmetric Attention Score of 15. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 13 May 2015.
All research outputs
#3,024,148
of 34,361,833 outputs
Outputs from Proceedings of the National Academy of Sciences of the United States of America
#33,208
of 118,929 outputs
Outputs of similar age
#7,332
of 111,047 outputs
Outputs of similar age from Proceedings of the National Academy of Sciences of the United States of America
#104
of 556 outputs
Altmetric has tracked 34,361,833 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 90th percentile: it's in the top 10% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 118,929 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 40.1. This one has gotten more attention than average, scoring higher than 71% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 111,047 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 92% of its contemporaries.
We're also able to compare this research output to 556 others from the same source and published within six weeks on either side of this one. This one has done well, scoring higher than 79% of its contemporaries.
