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The integrator complex is required for the synthesis of protein coding and non-coding RNA and contains the protein INTS13. Here, the authors find germline mutations in INTS13 in two families with oral facial digital syndrome and show that the mutation affects the c-terminal domain of the protein and disrupts cilliogenesis.

Upon Notch pathway activation, the receptor is cleaved to release the Notch intracellular domain (NICD), which translocates to the nucleus to activate gene transcription. Using Xenopus egg extracts, we have identified a Notch1-specific destruction signal (N1-Box). We show that mutations in the N1-Box inhibit NICD1 degradation and that the N1-Box is transferable for the promotion of degradation of heterologous proteins in Xenopus egg extracts and in cultured human cells. Mutation of the N1-Box enhances Notch1 activity in cultured human cells and zebrafish embryos. Human cancer mutations within the N1-Box enhance Notch1 signaling in transgenic zebrafish, highlighting the physiological relevance of this destruction signal. We find that binding of the Notch nuclear factor, CSL, to the N1-Box blocks NICD1 turnover. Our studies reveal a mechanism by which degradation of NICD1 is regulated by the N1-Box to minimize stochastic flux and to establish a threshold for Notch1 pathway activation.

Cdc14 is an evolutionarily conserved serine/threonine phosphatase. Originally identified in Saccharomyces cerevisiae as a cell cycle regulator, its role in other eukaryotic organisms remains unclear. In Drosophila melanogaster, Cdc14 is encoded by a single gene, thus facilitating its study. We found that Cdc14 expression is highest in the testis of adult flies and that cdc14 null flies are viable. cdc14 null female and male flies do not display altered fertility. cdc14 null males, however, exhibit decreased sperm competitiveness. Previous studies have shown that Cdc14 plays a role in ciliogenesis during zebrafish development. In Drosophila, sensory neurons are ciliated. We found that the Drosophila cdc14 null mutants have defects in chemosensation and mechanosensation as indicated by decreased avoidance of repellant substances and decreased response to touch. In addition, we show that cdc14 null mutants have defects in lipid metabolism and resistance to starvation. These studies highlight the diversity of Cdc14 function in eukaryotes despite its structural conservation.

Summary We previously reported that the small nuclear RNA processing complex, Integrator, is required for dynein recruitment to the nuclear envelope at mitotic onset in cultured human cells. We now report an additional role for INT in ciliogenesis. Depletion of INT subunits from cultured human cells results in loss of primary cilia. We provide evidence that the requirements for INT in dynein localization and ciliogenesis are uncoupled: proteins essential for ciliogenesis are not essential for dynein recruitment to the nuclear envelope, while depletion of known regulators of perinuclear dynein has minimal effects on ciliogenesis. Taken together, our data support a model in which INT ensures proper processing of distinct pools of transcripts encoding components that independently promote perinuclear dynein enrichment and ciliogenesis.