Microprocessor dynamics and interactions at endogenous imprinted C19MC microRNA genes.

Nuclear primary microRNA (pri-miRNA) processing catalyzed by the DGCR8-Drosha (Microprocessor) complex is highly regulated. Little is known, however, about how microRNA biogenesis is spatially organized within the mammalian nucleus. Here, we image for the first time, in living cells and at the level of a single microRNA cluster, the intranuclear distribution of untagged, endogenously-expressed pri-miRNAs generated at the human imprinted chromosome 19 microRNA cluster (C19MC), from the environment of transcription sites to single molecules of fully released DGCR8-bound pri-miRNAs dispersed throughout the nucleoplasm.

Genetic interactions show the importance of rRNA modification machinery for the role of Rps15p during ribosome biogenesis in S. cerevisiae.

Rps15p, an essential ribosomal protein, was previously shown to be critical for nuclear export of small subunit pre-particles. We have designed a synthetic lethal screen in Saccharomyces cerevisiae to identify its genetic partners and further elucidate its role during ribosomal biogenesis. Our screen revealed interactions with mutants affected at various stages during ribosome biogenesis, from early nucleolar steps to nuclear export.

Nuclear export competence of pre-40S subunits in fission yeast requires the ribosomal protein Rps2.

Ribosome biogenesis is an evolutionarily conserved pathway that requires ribosomal and nonribosomal proteins. Here, we investigated the role of the ribosomal protein S2 (Rps2) in fission yeast ribosome synthesis. As for many budding yeast ribosomal proteins, Rps2 was essential for cell viability in fission yeast and the genetic depletion of Rps2 caused a complete inhibition of 40S ribosomal subunit production.