There's a very interesting paper that's just been published online in ScienceExpress. The work is by Haung et al. (2013) from the Broad Institute at Harvard and MIT (Boston, Massachusetts, USA). These workers looked at the genomes of 70 different malignant melanomas and discovered that fifty (50) of them had mutations in the promoter region of the gene TERT (telomerase reverse transcriptase). The mutations created a new binding site for transcription factors resulting in a 2-4 fold increase in transcription of the gene.
Here's a picture of the gene from the Ensembl website [TERT]. The position of the transcription start site (P) is shown and the approximate position of the two mutations (M) is just upstream.
It's good that mutations affecting melanomas have been identified but the result isn't totally unexpected. We've known for fifty years that mutations in the promoter regions of genes can affect expression. Even in humans, such mutations have been widely studied; for example, lactase persistence is due to mutations in enhancer regions of the lactase gene.
Let's look at the press release from the Broad Institute [Genomic "dark matter" yields major melanoma discovery]. It's written by Paul Goldsmith who writes ..."This new finding represents an initial foray into the 'dark matter' of the cancer genome," said Levi Garraway, senior associate member of the Broad, and associate professor of medicine at Dana-Farber, the article’s senior author.
WTF! Since when have promoters and enhancers been called "dark matter"? And why isn't it mentioned, or even hinted at, in the published paper?Only about 1% of the human genome provides the blueprint for the body’s proteins. The remaining "non-coding" portion of the genome, sometimes referred to as dark matter, is poorly understood. Scientists have only recently begun exploring the relationship between these regions and the body’s cellular structure and processes.
We have an excellent understanding of the human genome [What's in Your Genome?]. This press release implies that only 1% of the genome is understood and the rest is mysterous "dark matter." We've known for decades that most of this DNA is junk (defective transposons). We know about pseudogenes, genes that encode functional RNAs, regulatory regions (including enhancers), introns, centromeres, defective viruses, telomeres, origins of replication, and several other functional parts of the genome.
I don't believe that the senior author of this study, Levi Garraway, actually believes what he is quoted as saying. If it were true then why didn't he put it in the paper? Why is there nothing in the paper about the importance of revealing mysterious "dark matter"?
Why do press releases have to be so misleading? Huang, F.W., Hodis, E., Xu, M.J., Kryukov, G.V., Chin, L., and Garraway, L.A. (2013) Highly Recurrent TERT Promoter Mutations in Human Melanoma. Science published online January 24 2013 [doi: 10.1126/science.1229259
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