Jose Sotelo a, b, Dominic Esposito b, c, Maria Ana Duhagon d, Kelley Banfield a, b, Jennifer Mehalko b, c Hongling Liao a, b, 1, Robert M. Stephens b, e, Timothy J. R. Harris b, David J. Munroe b, 2, and Xiaolin Wu a, b
a Laboratory of Molecular Technology, b Advanced
Technology Program, c Protein Expression Laboratory,
d Cancer Stem Cell Section, Laboratory of Cancer Prevention,
National Cancer Institute-Frederick, Frederick, MD, 21702, USA; and
e Advanced Biomedical Computing Center, SAIC-Frederick,
Inc., National Cancer Institute-Frederick, Frederick, MD 21702 USA
1 Present address: Sequencing Facility, Advanced Technology Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, MD 21702.
2 To whom correspondence should be addressed. E-mail:
dmunroe@mail.ncifcrf.gov
Edited* by David E. Housman, Massachusetts Institute of Technology,
Cambridge, MA, and approved December 16, 2009 (received for review June
18, 2009)
Author contributions: J.S., D.E., T.J.R.H., D.J.M., and X.W. designed research; J.S., D.E., M.A.D., K.B., J.M., and H.L. performed research; J.S., R.M.S., T.J.R.H., D.J.M., and X.W. analyzed data; and J.S., T.J.R.H., D.J.M., and X.W. wrote the paper.
Abstract:
Recent genomewide association studies have found multiple genetic variants on chromosome 8q24 that are significantly associated with an increased susceptibility to prostate, colorectal, and breast cancer. These risk loci are located in a ”gene desert,” a few hundred kilobases telomeric to the Myc gene. To date, the biological mechanism(s) underlying these associations remain unclear. It has been speculated that these 8q24 genetic variant(s) might affect Myc expression by altering its regulation or amplification status. Here, we show that multiple enhancer elements are present within this region and that they can regulate transcription of Myc. We also demonstrate that one such enhancer element physically interacts with the Myc promoter via transcription factor Tcf-4 binding and acts in an allele specific manner to regulate Myc expression.
This Direct Submission article had a prearranged editor.
The authors declare no conflict of interest.
This article contains supporting information online at:
http://www.pnas.org/cgi/content/full/0906067107/DCSupplemental
Supplemental Figure. 1. Effect of CMV Enhancer Element over Myc and TK Promoters.
Supplemental Figure. 1. Effect of CMV Enhancer Element over Myc and TK Promoters.
The CMV enhancer was cloned in front of a Myc promoter-driven or TK promoter-driven luciferase-GFP reporter. Luciferase activity was recorded in prostate cell lines LnCAP, and PC3 as well as colorectal cell line SW620. Enhancer reporter plasmids were co-transfected into cell lines as described in materials and methods. Luciferase activity was measured 24 hrs post-transfection using the Dual-Glo Luciferae assay system.
Supplemental Figure 2. Enhancer E interacts with Tcf-4 in vivo.
Supplemental Figure 2. Enhancer E interacts with Tcf-4 in vivo.
A. b-catenin/Tcf-4 can stimulate enhancer E activity in the luciferase reporter assay. Luciferase activity of Myc-luciferase constructs (with and without enhancer E (eE)) in prostate cell line LnCAP with/without (+/-) b-catenin and/or Tcf-4.
Supplemental table 1, 2, and 3. SNP rs6893267 influences enhancer E activity.
Luciferase activity of enhancer-Myc-luciferase constructs in prostate
cell line LnCAP with or without b-catenin /Tcf-4 (25ng of each plasmid).
The G and T allele variants of enhancer E are indicated.
1. Each cell retains all of its embryonic genes for a lifetime.
2. Controls for embryonic genes are often absent in adults.
3. Uncontrolled embryonic genes can replicate wildly.
4. Replicating genes participate in intra-cellular competition.
5. The basis for gene competition is selective transcription.
6. MicroRNAs can reprogram embryomic transcription.
7. Gene reprogramming can produce normal phenotypes.
8. Normal phenotypes can by-pass chromosomal lesions.
9. MicroRNA therapy may need to be permanent.
10. Transplantation of microRNAs could be preferred.
1. Pathways within cell genomes involve a flow of information.
2. Information can flow by direct contact or by third parties.
3. Direct contact within whole genomes is difficult to regulate.
4. DNA-DNA direct contects are influenced by agents.
5. Nuclear agents include hydrophilic ionic and hydrophobic conforming ligands.
6. Third parties within genomes involve RNAs and proteins.
7. RNAs and proteins are easy to regulate or reverse.
8. Information can be shared, lost, or transformed.
9. System information can be hidden during system isolation.
10. Local information can be permanently lost during system entropy.
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