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This Week in Cell: Apr 24, 2013

University of Massachusetts researcher Albertha Walhout and colleagues describe diet-related gene expression networks delineated multiple genetic screening methods. The group used a mutagenesis screen, RNA interference, and other approaches to track down a gene network involved in dietary response when Caenorhabditis elegans worms munch on Comamonas bacteria rather than their standard Escherichia coli fare. Through analyses of this set of 146 apparent activators and 38 repressors, the study authors unearthed "a transcriptional response system that is poised to sense dietary cues and metabolic imbalances, illustrating extensive communication between metabolic networks in the mitochondria and gene regulatory networks in the nucleus."

German researchers report on findings from an RNA interference-based search for genetic factors involved in liver regeneration. The team used small hairpin RNAs to systematically knock down genes in a mouse model of liver regeneration, looking for targets that enhanced or suppressed this liver regeneration. The search led them to a kinase-coding gene called MKK4 that seems to have a central regulatory role in liver regeneration. This process got a boost in mouse models when the gene is silenced, researchers found, even when underlying acute or chronic liver disease was present.

The succession of players that come together in protein complexes appears to be under evolutionary selection, according to a UK team, suggesting this assembly order contributes to biological function. The researchers considered protein assembly in general and in the context of proteins produced from fused genes. With the help of genome sequence data, for example, they found evidence that protein assembly pathways tend to be conserved in the face of gene fusion events. These and other data "reveal the intimate relationships among protein assembly, quaternary structure, and evolution," study authors say, "and demonstrate on a genome-wide scale the biological importance of ordered assembly pathways."