The effect of conventional and artificial diet on esterase band pattern inMyzus persicae (Sulzer)

Summary The esterase band pattern on a conventional potato leaf diet differs markedly from that in aphids of the same strain culture on an artificial diet. Possible reasons for these differences are discussed.S.B. acknowledges financial support from the Ministry of Agriculture, Fisheries and Food.     

Location of an eye mutant in the onion flyHylemya antiqua meigen using a pericentric chromosome inversion

Summary With the use of a pericentric inversion in chromosome 3, an eye color mutant in the onion fly was located in chromosome 3. No recombination occurs in males; 40.2% recombination was observed in females. This linkage through the male facilitates further cytogenetic research on structural aberrations involving chromosome 3.     

SUMO modification is required for in vivo Hox gene regulation by the Caenorhabditis elegans Polycomb group protein SOP-2

Post-translational modification of proteins by the ubiquitin-like molecule SUMO (sumoylation) regulates their subcellular localization and affects their functional properties in vitro, but the physiological function of sumoylation in multicellular organisms is largely unknown. Here, we show that the C. elegans Polycomb group (PcG) protein SOP-2 interacts with the SUMO-conjugating enzyme UBC-9 through its evolutionarily conserved SAM domain. Sumoylation of SOP-2 is required for its localization to nuclear bodies in vivo and for its physiological repression of Hox genes. Global disruption of sumoylation phenocopies a sop-2 mutation by causing ectopic Hox gene expression and homeotic transformations. Chimeric constructs in which the SOP-2 SAM domain is replaced with that derived from fruit fly or mammalian PcG proteins, but not those in which the SOP-2 SAM domain is replaced with the SAM domains of non-PcG proteins, confer appropriate in vivo nuclear localization and Hox gene repression. These observations indicate that sumoylation of PcG proteins, modulated by their evolutionarily conserved SAM domain, is essential to their physiological repression of Hox genes.