A shared role for RBF1 and dCAP-D3 in the regulation of transcription with consequences for innate immunity

Previously, we discovered a conserved interaction between RB proteins and the Condensin II protein CAP-D3 that is important for ensuring uniform chromatin condensation during mitotic prophase. The Drosophila melanogaster homologs RBF1 and dCAP-D3 co-localize on non-dividing polytene chromatin, suggesting the existence of a shared, non-mitotic role for these two proteins. Here, we show that the absence of RBF1 and dCAP-D3 alters the expression of many of the same genes in larvae and adult flies. Strikingly, most of the genes affected by the loss of RBF1 and dCAP-D3 are not classic cell cycle genes but are developmentally regulated genes with tissue-specific functions and these genes tend to be located in gene clusters. Our data reveal that RBF1 and dCAP-D3 are needed in fat body cells to activate transcription of clusters of antimicrobial peptide (AMP) genes. AMPs are important for innate immunity, and loss of either dCAP-D3 or RBF1 regulation results in a decrease in the ability to clear bacteria. Interestingly, in the adult fat body, RBF1 and dCAP-D3 bind to regions flanking an AMP gene cluster both prior to and following bacterial infection. These results describe a novel, non-mitotic role for the RBF1 and dCAP-D3 proteins in activation of the Drosophila immune system and suggest dCAP-D3 has an important role at specific subsets of RBF1-dependent genes

Object-Oriented Development for Open Systems

This paper outines the requirements for a series of tools to develop effectively systems in an object-oriented manner. It points out that reusability requires a certain change in philosophy and methodology for program development. 1 Introduction One of the oldest and most persistent problems in Computer Science has to do with the development of information systems. That is, how do we develop a system for a particular application which serves the user well. Over the years we coined different terms for describing the methodology and the tools used to solve the problem. We went from Systems Analysis and Programming to Software Engineering to Knowledge Engineering. In each case we used different techniques to develop the system, such as formal specification, high level languages, database systems and knowledge base systems. We retained however, the same overall systematic approach for developing the application. This approach, sometimes called the waterfall model for program development, ..