In this week's PNAS Early Edition, investigators at the University of Washington in Seattle report their proof-of-principle study, which validates the use of a bacterial porin for nanopore sequencing. "We demonstrate that the ionic current through the engineered Mycobacterium smegmatis porin A, MspA, has the ability to distinguish all four DNA nucleotides and resolve single-nucleotides in single-stranded DNA when double-stranded DNA temporarily holds the nucleotides in the pore constriction," the authors write.
This week, investigators in Australia and New Zealand report their use of a "modified ancient DNA extraction procedure to recover exogenous mitochondrial and nuclear DNA from the inside and outside surfaces of moa eggs." The extinct flightless moa, the authors write, "radiated rapidly into a large number of morphologically diverse species." In examining the DNA from 69 eggshells and six reconstructed "whole" eggs, the team found two distinct lineages within the Euryapteryx genus.
A trio of researchers at the Mount Sinai School of Medicine in New York show in PNAS this week that "RIG-I preferentially associates with shorter, 5'ppp containing viral RNA molecules in infected cells," which they determined using next-generation RNA sequencing. They also found that "during Sendai infection RIG-I specifically bound the genome of the defective interfering particle and did not bind the full-length virus genome or any other viral RNAs." In influenza-infected cells, RGI also associated with shorter genomic segments, the authors write.
Also in this week's PNAS, investigators at the University of Texas MD Anderson Cancer Center demonstrate that "RNA helicase A is a DNA-binding partner for EGFR-mediated transcriptional activation in the nucleus." Specifically, the team shows that RHA "is an important mediator for EGFR-induced gene transactivation. … Knockdown of RHA expression in cancer cells abrogates the binding of EGFR to the target gene promoter, thereby reducing EGF/EGFR-induced gene expression."