to Explore Nucleolar Stress.

Nucleolar stress occurs when ribosome production or function declines. Nucleolar stress in stem cells or progenitor cells often leads to disease states called ribosomopathies. offers a robust system to explore how nucleolar stress causes cell cycle arrest, apoptosis, or autophagy depending on the cell type.

Nucleolar stress in neuroblasts, a model for human ribosomopathies.

Different stem cells or progenitor cells display variable threshold requirements for functional ribosomes. This is particularly true for several human ribosomopathies in which select embryonic neural crest cells or adult bone marrow stem cells, but not others, show lethality due to failures in ribosome biogenesis or function (now known as nucleolar stress). To determine if various neuroblasts display differential sensitivities to nucleolar stress, we used CRISPR-Cas9 to disrupt the gene that encodes two splice variant ribosome biogenesis factors (RBFs).

Development of Anncaliia algerae (Microsporidia) in Drosophila melanogaster.

Representatives of the genus Anncaliia are known as natural parasites of dipteran and coleopteran insects, amphipod crustaceans, but also humans, primarily with immunodeficiency. Anncaliia algerae-caused fatal myositis is considered as an emergent infectious disease in humans. A.

The Nopp140 gene in Drosophila melanogaster displays length polymorphisms in its large repetitive second exon.

Nopp140, often called the nucleolar and Cajal body phosphoprotein (NOLC1), is an evolutionarily conserved chaperone for the transcription and processing of rRNA during ribosome subunit assembly. Metazoan Nopp140 contains an amino terminal LisH dimerization domain and a highly conserved carboxyl domain. A large central domain consists of alternating basic and acidic motifs of low sequence complexity.

R1 retrotransposons in the nucleolar organizers of Drosophila melanogaster are transcribed by RNA polymerase I upon heat shock.

The ribosomal RNA genes (rDNA) of Drosophila melanogaster reside within centromere-proximal nucleolar organizers on both the X and Y chromosomes. Each locus contains between 200-300 tandem repeat rDNA units that encode 18S, 5.8S, 2S, and 28S ribosomal RNAs (rRNAs) necessary for ribosome biogenesis.

Drosophila delta-1-pyrroline-5-carboxylate dehydrogenase (P5CDh) is required for proline breakdown and mitochondrial integrity-Establishing a fly model for human type II hyperprolinemia.

Delta-1-pyrroline-5-carboxylate dehydrogenase (P5CDh) is a nuclear-encoded mitochondrial enzyme that catalyzes the second step in proline degradation. Mutations in human P5CDh cause type II hyperprolinemia, a complex syndrome displaying increased serum proline and mental disabilities. Conceptual gene CG7145 in Drosophila melanogaster encodes the orthologous DmP5CDh1.

Knockdown of the Drosophila GTPase nucleostemin 1 impairs large ribosomal subunit biogenesis, cell growth, and midgut precursor cell maintenance.

Mammalian nucleostemin (NS) is a nucleolar guanosine triphosphate-binding protein implicated in cell cycle progression, stem cell proliferation, and ribosome assembly. Drosophila melanogaster contains a four-member nucleostemin family (NS1-4). NS1 is the closest orthologue to human NS; it shares 33% identity and 67% similarity with human NS.

Mycobacterium smegmatis histone-like protein Hlp is nucleoid associated.

Eubacteria encode proteins that are required for nucleoid organization and for regulation of DNA-dependent processes. Of these histone-like proteins (Hlps), Escherichia coli HU has been shown to associate with the nucleoid and to regulate processes such as DNA repair and recombination. In contrast, the divergent HU homologs encoded by mycobacteria have been variously identified as involved in the physiology of dormancy, in the response to cold shock, or as laminin-binding proteins associated with the cell envelope.

RNAi knockdown of Nopp140 induces Minute-like phenotypes in Drosophila.

Nopp140 associates with small nucleolar RNPs to chaperone pre-rRNA processing and ribosome assembly. Alternative splicing yields two isoforms in Drosophila: Nopp140-True is homologous to vertebrate Nopp140 particularly in its carboxy terminus, whereas Nopp140-RGG contains a glycine and arginine-rich (RGG) carboxy terminus typically found in vertebrate nucleolin. Loss of ribosome function or production at critical points in development leads to Minute phenotypes in Drosophila or the Treacher Collins syndrome (TCS) in humans.

Cell and molecular biology of nucleolar assembly and disassembly.

Nucleoli disassemble in prophase of the metazoan mitotic cycle, and they begin their reassembly (nucleologenesis) in late anaphase?early telophase. Nucleolar disassembly and reassembly were obvious to the early cytologists of the eighteenth and nineteenth centuries, and although this has lead to a plethora of literature describing these events, our understanding of the molecular mechanisms regulating nucleolar assembly and disassembly has expanded immensely just within the last 10-15 years. We briefly survey the findings of nineteenth-century cytologists on nucleolar assembly and disassembly, followed by the work of Heitz and McClintock on nucleolar organizers.

Deletion and site-specific mutagenesis of nucleolin's carboxy GAR domain.

Vertebrate nucleolin is an abundant RNA-binding protein in the dense fibrillar component of active nucleoli. Nucleolin is modular in composition. Its amino-terminal third contains alternating acidic and basic domains, its middle section contains four consensus RNA-binding domains (cRBDs), and its carboxy-terminus contains a distinctive glycine/arginine-rich (GAR) domain with several RGG motifs.

Nucleolin is a calcium-binding protein.

We have purified a prominent 110-kDa protein (p110) from 1.6 M NaCl extracts of rat liver nuclei that appears to bind Ca2+. p110 was originally identified by prominent blue staining with 'Stains-All' in sodium dodecyl sulfate-polyacrylamide gels and was observed to specifically bind ruthenium red and 45Ca2+ in nitrocellulose blot overlays.

Two splice variants of Nopp140 in Drosophila melanogaster.

The Nopp140 gene of Drosophila maps within 79A5 of chromosome 3. Alternative splicing yields two variants. DmNopp140 (654 residues) is the sequence homolog of vertebrate Nopp140.