A YY1-dependent increase in aerobic metabolism is indispensable for intestinal organogenesis

During late gestation, villi extend into the intestinal lumen to dramatically increase the surface area of the intestinal epithelium, preparing the gut for the neonatal diet. Incomplete development of the intestine is the most common gastrointestinal complication in neonates, but the causes are unclear. We provide evidence in mice that Yin Yang 1 (Yy1) is crucial for intestinal villus development. YY1 loss in the developing endoderm had no apparent consequences until late gestation, after which the intestine differentiated poorly and exhibited severely stunted villi. Transcriptome analysis revealed that YY1 is required for mitochondrial gene expression, and ultrastructural analysis confirmed compromised mitochondrial integrity in the mutant intestine. We found increased oxidative phosphorylation gene expression at the onset of villus elongation, suggesting that aerobic respiration might function as a regulator of villus growth. Mitochondrial inhibitors blocked villus growth in a fashion similar to Yy1 loss, thus further linking oxidative phosphorylation with late-gestation intestinal development. Interestingly, we find that necrotizing enterocolitis patients also exhibit decreased expression of oxidative phosphorylation genes. Our study highlights the still unappreciated role of metabolic regulation during organogenesis, and suggests that it might contribute to neonatal gastrointestinal disorders

Seawi—a sea urchin piwi/argonaute family member is a component of MT-RNP complexes

This is the publisher's version, also available electronically from http://rnajournal.cshlp.org/content/11/5/646.The piwi/argonaute family of proteins is involved in key developmental processes such as stem cell maintenance and axis specification through molecular mechanisms that may involve RNA silencing. Here we report on the cloning and characterization of the sea urchin piwi/argonaute family member seawi. Seawi is a major component of microtubule-ribonucleoprotein (MT-RNP) complexes isolated from two different species of sea urchin, Strongylocentrotus purpuratus and Paracentrotus lividus. Seawi co-isolates with purified ribosomes, cosediments with 80S ribosomes in sucrose density gradients, and binds microtubules. Seawi possesses the RNA binding motif common to piwi family members and binds P. lividus bep4 mRNA, a transcript that co-isolates with MT-RNP complexes and whose translation product has been shown to play a role in patterning the animal–vegetal axis. Indirect immunofluorescence studies localized seawi to the cortex of unfertilized eggs within granule-like particles, the mitotic spindle during cell division, and the small micromeres where its levels were enriched during the early cleavage stage. Lastly, we discuss how seawi, as a piwi/argonaute family member, may play a fundamentally important role in sea urchin animal–vegetal axis formation and stem cell maintenance

Luminescent Boron Quinolate Block Copolymers via RAFT Polymerization

The preparation of well-defined luminescent organoboron quinolate block copolymers via sequential RAFT polymerization is reported. Boron-containing block copolymers with PS, P­(St-<i>alt</i>-MAh), and PNIPAM as the second block were successfully synthesized. The photophysical properties of the block copolymers were studied by UV–vis and fluorescence spectroscopy. Independent of the second block, the boron quinolate block copolymers that contain the parent 8-hydroxyquinolato ligand (PM1-<i>b</i>-PS, PM1-<i>b</i>-PNIPAM, PM1-<i>b</i>-P­(St-<i>alt</i>-MAh)) are green luminescent, whereas a polymer with 5-(4-dimethylaminophenyl)-8-hydroxyquinolate as the ligand (PM2-<i>b</i>-PS) shows red luminescence. The P­(St-<i>alt</i>-MAh)-based block copolymer was further modified with photoactive azobenzene groups. The self-assembly behavior of the amphiphilic block copolymers was studied by transmission electron microscopy (TEM) and dynamic light scattering (DLS). In water, PM1-<i>b</i>-PNIPAM forms spherical micelles. The azobenzene-modified P­(St-<i>alt</i>-AbMA)-<i>b</i>-PM1 exhibits a solvent-dependent self-assembly behavior in basic solutions, and large spindle-shaped aggregates and spherical micelles were observed

Electron-Deficient Triarylborane Block Copolymers: Synthesis by Controlled Free Radical Polymerization and Application in the Detection of Fluoride Ions

Luminescent triarylborane homo and block copolymers with well-defined chain architectures were synthesized via reversible addition–fragmentation chain transfer polymerization of a vinyl-functionalized borane monomer. The Lewis acid properties of the polymers were exploited in the luminescent detection of fluoride ions. A dual-responsive fluoride sensor was developed by taking advantage of the reversible self-assembly of a PNIPAM-based amphiphilic block copolymer. Anion detection in aqueous solution was realized by introducing positively charged pyridinium moieties along the polymer chain

Seawi—a sea urchin piwi/argonaute family member is a component of MT-RNP complexes

The piwi/argonaute family of proteins is involved in key developmental processes such as stem cell maintenance and axis specification through molecular mechanisms that may involve RNA silencing. Here we report on the cloning and characterization of the sea urchin piwi/argonaute family member seawi. Seawi is a major component of microtubule-ribonucleoprotein (MT-RNP) complexes isolated from two different species of sea urchin, Strongylocentrotus purpuratus and Paracentrotus lividus. Seawi co-isolates with purified ribosomes, cosediments with 80S ribosomes in sucrose density gradients, and binds microtubules. Seawi possesses the RNA binding motif common to piwi family members and binds P. lividus bep4 mRNA, a transcript that co-isolates with MT-RNP complexes and whose translation product has been shown to play a role in patterning the animal–vegetal axis. Indirect immunofluorescence studies localized seawi to the cortex of unfertilized eggs within granule-like particles, the mitotic spindle during cell division, and the small micromeres where its levels were enriched during the early cleavage stage. Lastly, we discuss how seawi, as a piwi/argonaute family member, may play a fundamentally important role in sea urchin animal–vegetal axis formation and stem cell maintenance