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Methylation on the base or the ribose is prevalent in eukaryotic ribosomal RNAs (rRNAs) and is thought to be crucial for ribosome biogenesis and function. Artificially introduced 2'-O-methyl groups in small interfering RNAs (siRNAs) can stabilize siRNAs in serum without affecting their activities in RNA interference in mammalian cells. Here, we show that(More)
We identified DN-cadherin, a novel Drosophila cadherin that is expressed in axons and in the mesoderm. Although DN-cadherin has diverged from vertebrate classic cadherins in terms of its extracellular structure, it still can form a complex with catenins and induce cell aggregation, as do the vertebrate molecules. Loss-of-function mutations of the gene(More)
In the Drosophila female the product of the germline stem cell, the cystoblast, gives rise to 16 interconnected cystocytes. One of them differentiates into the oocyte, while the 15 others become polyploid nurse cells. Bic-D is required for the differentiation of an oocyte and hence for fertility. Recessive mutations in Bic-D block the oocyte-specific(More)
Lis1 is required for nuclear migration in fungi, cell cycle progression in mammals, and the formation of a folded cerebral cortex in humans. Lis1 binds dynactin and the dynein motor complex, but the role of Lis1 in many dynein/dynactin-dependent processes is not clearly understood. Here we generate and/or characterize mutants for Drosophila Lis1 and a(More)
The formation of dorsal-ventral polarity in Drosophila requires the asymmetric nuclear localization of the dorsal protein along the D/V axis. This process is regulated by the action of the dorsal group genes and cactus. We show that dorsal and cactus are both phosphoproteins that form a stable cytoplasmic complex, and that the cactus protein is stabilized(More)
Haplo-insufficiency of human Lis1 causes lissencephaly. Reduced Lis1 activity in both humans and mice results in a neuronal migration defect. Here we show that Drosophila Lis1 is highly expressed in the nervous system. Lis1 is essential for neuroblast proliferation and axonal transport, as shown by a mosaic analysis using a Lis1 null mutation. Moreover, it(More)
We describe distinct patterns of histone methylation during human cell cycle progression. Histone H4 methyltransferase activity was found to be cell cycle-regulated, consistent with increased H4 Lys 20 methylation at mitosis. This increase closely followed the cell cycle-regulated expression of the H4 Lys 20 methyltransferase, PR-Set7. Localization of(More)
The Drosophila gene, dorsal, is a maternal effect locus that is essential for the establishment of dorsal-ventral polarity in the developing embryo. The dorsal protein was predicted from the complementary DNA sequence; it is almost 50 percent identical, over an extensive region, to the protein encoded by the avian oncogene v-rel, its cellular homolog,(More)
PR-Set7 is a histone methyltransferase that specifically monomethylates histone H4 lysine 20 (K20) and is essential for cell proliferation. Our results show that in PR-Set7 mutants, the DNA damage checkpoint is activated. This phenotype is manifested by reduction in both the mitotic and the S phase indexes, a delay in the progression through early mitosis,(More)
dorsal is one of the maternally active dorsal-ventral polarity genes of Drosophila and is homologous to the vertebrate proto-oncogene c-rel. In wild-type embryos, the dorsal protein is found in the cytoplasm during cleavage. After the nuclei migrate to the periphery of the embryo, a ventral-to-dorsal gradient of nuclear dorsal protein is established. The(More)