The Drosophila melanogaster host model

The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen–host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial–host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis–host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed

A novel multidomain transcription coactivator SAYP can also repress transcription in heterochromatin

Enhancers of yellow (e(y)) is a group of genetically and functionally related genes for proteins involved in transcriptional regulation. The e(y)3 gene of Drosophila considered here encodes a ubiquitous nuclear protein that has homologues in other metazoan species. The protein encoded by e(y)3, named Supporter of Activation of Yellow Protein (SAYP), contains an AT-hook, two PHD fingers, and a novel evolutionarily conserved domain with a transcriptional coactivator function. Mutants expressing a truncated SAYP devoid of the conserved domain die at a midembryonic stage, which suggests a crucial part for SAYP during early development. SAYP binds to numerous sites of transcriptionally active euchromatin on polytene chromosomes and coactivates transcription of euchromatin genes. Unexpectedly, SAYP is also abundant in the heterochromatin regions of the fourth chromosome and in the chromocenter, and represses the transcription of euchromatin genes translocated to heterochromatin; its PHD fingers are essential to heterochromatic silencing. Thus, SAYP plays a dual role in transcription regulation in euchromatic and heterochromatic regions