Cullin 4B is recruited to tristetraprolin-containing messenger ribonucleoproteins and regulates TNF-α mRNA polysome loading.

TNF-α is a central mediator of inflammation and critical for host response to infection and injury. TNF-α biosynthesis is controlled by transcriptional and posttranscriptional mechanisms allowing for rapid, transient production. Tristetraprolin (TTP) is an AU-rich element binding protein that regulates the stability of the TNF-α mRNA.

Identification of a nuclear carbonic anhydrase in Caenorhabditis elegans.

Background: Carbonic anhydrases (CA) catalyze the inter-conversion of CO(2) with HCO(3) and H(+), and are involved in a wide variety of physiologic processes such as anion transport, pH regulation, and water balance. In mammals there are sixteen members of the classical α-type CA family, while the simple genetic model organism Caenorhabditis elegans codes for six αCA isoforms (cah-1 through cah-6).

Methods: Fluorescent reporter constructs were used to analyze gene promoter usage, splice variation, and protein localization in transgenic worms.

CARHSP1 is required for effective tumor necrosis factor alpha mRNA stabilization and localizes to processing bodies and exosomes.

Tumor necrosis factor alpha (TNF-α) is a critical mediator of inflammation, and its production is tightly regulated, with control points operating at nearly every step of its biosynthesis. We sought to identify uncharacterized TNF-α 3' untranslated region (3'UTR)-interacting proteins utilizing a novel screen, termed the RNA capture assay. We identified CARHSP1, a cold-shock domain-containing protein.

Oscillatory transepithelial H(+) flux regulates a rhythmic behavior in C. elegans.

In C. elegans, rhythmic defecation is timed by oscillatory Ca(2+) signaling in the intestine [1-5]. Here, by using fluorescent biosensors in live, unrestrained worms, we show that intestinal pH also oscillates during defecation and that transepithelial proton movement is essential for defecation signaling.

A computational analysis of central CO2 chemosensitivity in Helix aspersa.

We created a single-compartment computer model of a CO(2) chemosensory neuron using differential equations adapted from the Hodgkin-Huxley model and measurements of currents in CO(2) chemosensory neurons from Helix aspersa. We incorporated into the model two inward currents, a sodium current and a calcium current, three outward potassium currents, an A-type current (I(KA)), a delayed rectifier current (I(KDR)), a calcium-activated potassium current (I(KCa)), and a proton conductance found in invertebrate cells. All of the potassium channels were inhibited by reduced pH.