Genome-wide characterization of light-inducible responses reveals a hierarchical light-sensing cascade in N. crassa

ABSTRACT: To better understand the roles of WC-1, WC-2 and other putative photoreceptors in mediation of light signals and to identify new components in light sensing cascades, we used microarrays with genome-wide coverage to characterize light-inducible transcriptional changes in Neurospora crassa. After unsupervised hierarchical clustering of 90 microarrays, 316 genes, representing about 3.21% of the total genome, showed robust and consistent light responses. As expected, WC-1 and WC-2 knockout strains both exhibited severe impairments in response to a continuous white light stimulus, confirming their dominant roles in light sensing cascades. Knockout strains of 5 newly-identified light-inducible transcription factors were further characterized for their potential function in mediating light signals. Interestingly, one early light-inducible transcription factor, Submerged Protoperithecia-1 (SUB-1), appeared to be essential in mediating a large number of late light response, providing a direct molecular connection between early and late light responses. Furthermore, a novel motif, which is overrepresented among late light responsive genes, was demonstrated to be necessary for full induction of late light responses in vivo. Taken together, these results reveal a simple hierarchical light-sensing cascade in Neurospora, which is initially invoked by light-activated White Collar Complex (WCC) binding to Light Response Elements (LREs) of the primary target genes, including SUB-1. Subsequently, the induction of SUB-1 and other activators activate downstream targets. Thus, light responses of well-defined timing and amplitude can be orchestrated to meet the differential needs of underlying biological processes. Keywords: time course, light response

ORGANISM(S): Neurospora crassa

PROVIDER: GSE8932 | GEO | 2009/03/09

SECONDARY ACCESSION(S): PRJNA102345

REPOSITORIES: GEO