GenomeRNAi - a database for RNAi phenotypes and reagents
TitleScreen TitleAssayBiomodelSpecies
Genome-wide siRNA-based functional genomics of pigmentation identifies novel genes and pathways that impact melanogenesis in human cells. Ganesan et al. (2008) Melanogenesis Melanin protein expression and viabilityMNT-1H. sapiens

Abstract

Melanin protects the skin and eyes from the harmful effects of UV irradiation, protects neural cells from toxic insults, and is required for sound conduction in the inner ear. Aberrant regulation of melanogenesis underlies skin disorders (melasma and vitiligo), neurologic disorders (Parkinson''s disease), auditory disorders (Waardenburg''s syndrome), and opthalmologic disorders (age related macular degeneration). Much of the core synthetic machinery driving melanin production has been identified; however, the spectrum of gene products participating in melanogenesis in different physiological niches is poorly understood. Functional genomics based on RNA-mediated interference (RNAi) provides the opportunity to derive unbiased comprehensive collections of pharmaceutically tractable single gene targets supporting melanin production. In this study, we have combined a high-throughput, cell-based, one-well/one-gene screening platform with a genome-wide arrayed synthetic library of chemically synthesized, small interfering RNAs to identify novel biological pathways that govern melanin biogenesis in human melanocytes. Ninety-two novel genes that support pigment production were identified with a low false discovery rate. Secondary validation and preliminary mechanistic studies identified a large panel of targets that converge on tyrosinase expression and stability. Small molecule inhibition of a family of gene products in this class was sufficient to impair chronic tyrosinase expression in pigmented melanoma cells and UV-induced tyrosinase expression in primary melanocytes. Isolation of molecular machinery known to support autophagosome biosynthesis from this screen, together with in vitro and in vivo validation, exposed a close functional relationship between melanogenesis and autophagy. In summary, these studies illustrate the power of RNAi-based functional genomics to identify novel genes, pathways, and pharmacologic agents that impact a biological phenotype and operate outside of preconceived mechanistic relationships.

Screen details


Stable Id: GR00056-A
Screen title: Melanogenesis
Assay: Melanin protein expression and viability
Method: Absorbance and luminescence
Scope: Genome-wide
Screen type: Cell-based
Species: Homo sapiens
Biosource: Cell line
Biomodel: MNT-1
Library: Dharmacon, rp
Reagent type: siRNA
Score type: Normalized absorbance ratio
Cutoff: > 2 standard deviations below mean
Notes: Additional information about a secondary screen (retest to determine false-positive rate)