Project description:Post-translational modifications (PTMs) on histones have been found to play diverse functions in regulating chromatin events and gene expression. The operation of circadian clocks heavily relies on finely tuned and timely expression of the proteins comprising core oscillators. However, most studies of PTMs' effects on circadian clocks have been conducted using static systems in which circadian clocks are rendered arrhythmic due to the essential role of PTMs on gene expression. In the Neurospora circadian system, the White Collar Complex (WCC), a heterodimeric transcription factor formed from White Collar-1 (WC-1) and White Collar-2 (WC-2), serves the function of the BMAL1/CLOCK heterodimer in mammals, driving expression of circadian negative arm component(s), a principal one in Neurospora encoded by the gene frequency (frq). FRQ interacts with FRH (FRQ-interacting helicase) and CK-1 forming a stable complex that represses its own expression by inhibiting WCC. In this study, a genetic screen identified a gene, designated as eaf-8, that encodes a novel conserved subunit of the NuA4 histone acetylation complex. Loss of eaf-8 reduces H4 acetylation and RNA polymerase (Pol) II occupancy at frq and other known circadian genes, and leads to a long circadian period, delayed phase, and defective overt circadian output at some temperatures. In addition to strongly associating with the NuA4 histone acetyltransferase complex, EAF-8 is also found complexed with the transcription elongation regulator BYE-1. Expression of eaf-8, bye-1, histone hH2Az, and several NuA4 subunits is controlled by the circadian clock, indicating that the molecular clock both regulates the basic chromatin status and is regulated by changes in chromatin. Taken together, our data identify a new type of the NuA4 complex including EAF-8 and BYE-1 which, along with conventional NuA4 subunits, is required for timely and dynamic frq expression and thereby a normal and persistent circadian rhythm.
Project description:The suprachiasmatic nucleus (SCN) acts as the central clock to coordinate circadian oscillations in mammalian behavior, physiology and gene expression. Despite our knowledge of the circadian transcriptome of the SCN, how it impacts genome-wide protein expression is not well understood. Here, we interrogated the murine SCN proteome across the circadian cycle using SILAC-based quantitative mass spectrometry.
Project description:A. foliaceus secretory / excretory products (SEPs) were collected from 560 active adult parasites and identified and characterised using LC-ESI-MS/MS analysis.
Project description:The circadian clock is comprised of proteins that form negative feedback loops, which regulate the timing of global gene expression in a coordinated 24 hour cycle. As a result, the plant circadian clock is responsible for regulating numerous physiological processes central to growth and survival. To date, most plant circadian clock studies have relied on diurnal transcriptome changes to elucidate molecular connections between the circadian clock and observable phenotypes in wild-type plants. Here, we have combined high-throughput RNA-sequencing and mass spectrometry to comparatively characterize the lhycca1, prr7prr9, gi and toc1 circadian clock mutant rosette transcriptome and proteome at the end-of-day and end-of-night.
