1. Telomeres to the rescue
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Crystal structure of parallel quadruplexes from human telomeric DNA
Image: Wikimedia commons | The shortening of telomeres is associated with aging-dependent tissue degeneration, stem cell depletion, and organ failure. By reactivating telomerase and lengthening telomeres in old, telomerase-deficient mice, the degeneration processes can be reversed, restoring damaged tissues to almost full functionality. M. Jaskelioff, et al., "Telomerase reactivation reverses tissue degeneration in aged telomerase-deficient mice," Nature, 469:102-6, 2011. Evaluations by Igor Kogut and John Cambier, National Jewish Med and Research Center; Charles Streuli, Univ of Manchester; William Hahn, Dana Farber Cancer Inst; Preston Estep and Martha Bulyk, Brigham and Women's Hosp, Harvard Med School; Tobias Dansen and Boudewijn Burgering, Univ of Utrecht. Free F1000 Evaluation 2. Meet the ribosome For the first time, researchers detail the crystal structure of the smaller, 40S subunit of the eukaryotic ribosome. The structure reveals the fold of the subunit's entire ribosomal RNA and all 33 associated proteins, 18 of which have no homologues in bacterial ribosomes. J. Rabl et al., "Crystal structure of the eukaryotic 40S ribosomal subunit in complex with initiation factor 1," Science, 331:730-6, 2011. Evaluations by Daniel Gallie, Univ of California; Daniel Wilson, Ludwig Maximilian Univ Munich. Free F1000 Evaluation 3. Cellular cross-talk Telomere shortening and mitochondrial dysfunction have both independently been linked to aging and tissue degeneration. Now, it appears, they are directly linked to each other: telomere dysfunction activates tumor suppressor protein p53, which in turn binds and represses two promoters known to be master regulators of mitochondrial function. E. Sahin, et al., "Telomere dysfunction induces metabolic and mitochondrial compromise," Nature, 470:359-65, 2011. Evaluations by Lucio Comai, Keck School of Med, Univ of Southern California; Kevin Conley, Univ of Washington. Free F1000 Evaluation 4. Nucleotide mismatch Watson and Crick are right once again. Spontaneous DNA mutations can result from rare alternate base structures that form mismatches with other bases while still preserving the structure of a double helix -- a hypothesis the duo proposed over 50 years ago. A type of human DNA polymerase is shown to incorrectly insert a thymine opposite an alternate form of guanine while maintaining the correct structure. K. Bebenek, et al., "Replication infidelity via a mismatch with Watson-Crick geometry," Proc Natl Acad Sci, 108:1862-7, 2011. Evaluations by Ulrich Hubscher, Univ of Zurich; Rieko Yajima and Katsu Murakami, Pennsylvania State Univ. Free F1000 Evaluation 5. DNA bodyguards To protect DNA sites damaged during genome duplication, a p53-binding protein called 53BP1 appears to sequester the fragile region in nuclear compartments, shielding the lesions from further damage throughout most of mitosis. C. Lukas, et al., "53BP1 nuclear bodies form around DNA lesions generated by mitotic transmission of chromosomes under replication stress," Nat Cell Biol, 13:243-53, 2011. Evaluations by Antony Carr, Univ of Sussez; Junjie Chen, Univ of Texas M. D. Anderson Cancer Center. Free F1000 Evaluation 6. Dissecting traits In fruit flies, the phenotypic effect of a single quantitative trait loci (QTL) -- a stretch of genes that underlies some trait -- for abdominal pigmentation actually results from the cumulative action of over 50 smaller sequence variations in a variety of functional regions, demonstrating that a single QTL may actually be the collective result of many different molecular mechanisms. R.D. Bickel, et al., "Composite effects of polymorphisms near multiple regulatory elements create a major-effect QTL," PLoS Genet, 7:e1001275, 2011. Evaluations by Deborah Charlesworth, Univ of Edinburgh; Casey McNeil and Stuart Macdonald, Univ of Kansas. Free F1000 Evaluation 7. Noisy E. coli Genetically identical cells may be far more different than previously believed. There is striking variation in levels of gene expression among genetically identical E. coli cells, "noise" that may simply result from chance: With only a few copies of transcribing complexes at a given moment, the mRNA and proteins expressed in a single E. coli cell can appear random. Y. Taniguchi, et al., "Quantifying E. coli proteome and transcriptome with single-molecule sensitivity in single cells," Science, 329:533-8, 2010. Evaluation by Daniel Hebenstreit and Sarah Teichmann, MRC Laboratory of Mol Biol. Free F1000 Evaluation The F1000 Top 7 is a snapshot of the highest ranked articles from a 30-day period on Faculty of 1000 Genetics and Genomics, as calculated on March 31, 2011. Faculty Members evaluate and rate the most important papers in their field. To see the latest rankings, search the database, and read daily evaluations, visit http://f1000.com. Related stories:
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