In a paper published online in advance in Nature this week, the Cold Spring Harbor Laboratory's Michael Wigler et al. report their use of whole-genome amplification and next-gen sequencing on flow-sorted nuclei isolated from polygenomic tumor cells to determine that, "in contrast to gradual models of tumor progression, our data indicate that tumors grow by punctuated clonal expansions with few persistent intermediates."
Researchers at Rockefeller University, New York University, and Princeton University show that in Caenorhabditis elegans, the decision to leave a food patch "is a multigenic trait regulated in part by naturally occurring non-coding polymorphisms in tyra-3, which encodes a G-protein-coupled catecholamine receptor relates to vertebrate adrenergic receptors." As tyra-3 acts in sensory neurons, the team suggests that it detects internal catecholamines and responds according to environmental conditions. "These results indicate that genetic variation and environmental cues converge on common circuits to regulate behavior," the authors write.
A team led by investigators at Harvard Medical School reports online in advance in Nature this week on how telomeric repeat-containing RNA and replication protein A 1 organize an RPA-to-protection of telomerase 1 switch on telomeric single-stranded DNA. More specifically, the team shows that these molecules collectively work to "displace RPA from telomeric ssDNA after DNA replication, and promote telomere capping to preserve genomic integrity."
In this week's issue, researchers at Switzerland's University of Geneva show that in heat-stressed Arabidopsis seedlings, the ONSEN retrotransposon becomes trancriptionally active and synthesizes extrachromosomal DNA copies. "After stress, both ONSEN transcripts and extrachromosomal DNA gradually decayed and were no longer detected after 20 [to] 30 days," the team writes. However, the team observed a high frequency of new ONSEN insertions in the progeny of Arabidopsis plants deficient in siRNAs that were subjected to heat stress. "Retrotransposition was not observed in the progeny of wild-type plants subjected to stress or in non-stressed mutant controls, pointing to a crucial role of the siRNA pathway in restricting retrotransposition triggered by environmental stress," the Geneva team writes.