In this week’s Nature Genetics, a group of Harvard University researchers report the sequences of the genomes of a collection of Streptococcus pneumonia, the pathogen responsible for pneumonia, bacteraemia, and meningitis. The scientists sequenced the whole genomes of 616 asymptomatically carried pneumococci, obtained from children living in Massachusetts between 2000 and 2007, and found that the pneumococcal population was disrupted by the introduction of the 7-valent pneumococcal conjugate vaccine and that changes in pneumococcal serotype are largely responsible for the decline in invasive pneumococcal disease afterwards.
Also in Nature Genetics, a Stanford University team published the results of a proteomic and bioinformatics analysis of SWI/SNF complexes, known to be tumor suppressors, uncovering greater than expected roles in human malignancies. A proteomic analysis of endogenous mammalian SWI/SNF complexes revealed several new dedicated, stable subunits not found in yeast SWI/SNF complexes. The investigators also found that mammalian SWI/SNF subunits are mutated in 19.6 percent of all human tumors reported in 44 studies, suggesting that specific subunits protect against cancer in specific tissues. They also discovered that mutations affecting more than one subunit are “prevalent in certain cancers.” Taken together, the data indicate that proper functioning of polymorphic SWI/SNF complexes may constitute a “major mechanism of tumor suppression.”