The ISWI Chromatin-Remodeling Protein Is Required for Gene Expression and the Maintenance of Higher Order Chromatin Structure In Vivo

Abstract

Drosophila ISWI, a highly conserved member of the SWI2/SNF2 family of ATPases, is the catalytic subunit of three chromatin-remodeling complexes: NURF, CHRAC, and ACF. To clarify the biological functions of ISWI, we generated and characterized null and dominant-negative ISWI mutations. We found that ISWI mutations affect both cell viability and gene expression during Drosophila development. ISWI mutations also cause striking alterations in the structure of the male X chromosome. The ISWI protein does not colocalize with RNA Pol II on salivary gland polytene chromosomes, suggesting a possible role for ISWI in transcriptional repression. These findings reveal novel functions for the ISWI ATPase and underscore its importance in chromatin remodeling in vivo.

Parental RNA interference of genes involved in embryonic development of the western corn rootworm, Diabrotica virgifera virgifera LeConte

“…Since the functions of chromatin remodelers confer epigenetic effects that lead to stable changes in gene expression, short-term exposure to dsRNA in the ovary or in the embryo may lead to long-lasting RNAi-induced phenotype. Mutations in other members of the chromatin remodeler gene group are known to have gametogenic and/or embryonic effects in fruit flies (Daubresse et al, 1999;Deuring et al, 2000;Kehle et al, 1998;McDaniel et al, 2008); it remains to be seen if these genes would also serve as efficacious pRNAi targets for pest insect control. The ability of western corn rootworm to develop resistance to crop protection chemistries (Gray et al, 2009;Narva et al, 2013) and transgenic insect resistance traits based on Bt proteins (Gassmann et al, 2011) creates the need for new approaches to corn rootworm control to combine with existing technology.…”

Use of chromatin remodeling ATPases as RNAi targets for parental control of western corn rootworm (Diabrotica virgifera virgifera) and Neotropical brown stink bug (Euschistus heros)

“…In Drosophila, chromatin remodeling ATPases are known to have roles in both oogenesis and development. The Drosophila chromatin remodeling ATPases that are essential for oogenesis include Iswi (Deuring et al, 2000), Chd1 (McDaniel et al, 2008), Mi-2 (Kehle et al, 1998), and possibly Brm (He et al, 2014). In addition to oviposition defects, it was reported that the lack of maternal iswi leads to developmental arrest in an early stage of oogenesis (Deuring et al, 2000).…”

Interplay between chromatin remodelers and protein arginine methyltransferases

“…Currently ISWI complexes have been found in a variety of organisms from yeast to humans Ito et al, 1997;Varga-Weisz et al, 1997). In Drosophila, localization of ISWI protein on polytene chromosomes shows a lack of colocalization with the bulk of RNA polymerase II, suggesting that ISWI complexes are involved in processes other than transcription (Deuring et al, 2000;reviewed in Dirscherl and Krebs, 2004).…”