In nuclear pre-messenger RNA splicing, introns are excised by the spliceosome, a dynamic machine composed of both proteins and small nuclear RNAs (snRNAs). Over thirty years ago, after the discovery of self-splicing group II intron RNAs, the snRNAswere proposed to catalyse splicing. However, no definitive evidence for a role of either RNAor protein in catalysis by the spliceosome has been repor...

At the end of protein-coding genes, RNA polymerase (Pol) II undergoes a concerted transition that involves 3'-processing of the pre-mRNA and transcription termination. Here, we present a genome-wide analysis of the 3'-transition in budding yeast. We find that the 3'-transition globally requires the Pol II elongation factor Spt5 and factors involved in the recognition of the polyadenylation (pA)...

The machinery mediating chromosome condensation is poorly understood. To begin to dissect the in vivo function(s) of individual components, we monitored mitotic chromosome structure in mutants of condensin, cohesin, histone H3, and topoisomerase II (topo II). In budding yeast, both condensation establishment and maintenance require all of the condensin subunits, but not topo II activity or phos...

How does a virus bud from the plasma membrane of its host? Here we investigate several possible rate-limiting processes, including thermal fluctuations of the plasma membrane, hydrodynamic interactions, and diffusion of the glycoprotein spikes. We find that for bending moduli greater than 3 x 10(-13) ergs, membrane thermal fluctuations are insufficient to wrap the viral capsid, and the mechanic...

As a major actor of cellular trafficking, COPI coat proteins assemble on membranes and locally bend them to bud 60 nm-size coated particles. Budding requires the energy of the coat assembly to overcome the one necessary to deform the membrane which primarily depends on the bending modulus and surface tension, γ. Using a COPI-induced oil nanodroplet formation approach, we modulated the budding o...

This study examines the mechanism utilized by different MARCH proteins to restrict retrovirus infection. block incorporation of envelope glycoproteins budding virions.

The propagation of Persian walnut (Juglans regia) using grafting or budding is often difficult due to envi­ronmental factors. Temperature fluctuation and plant water status affect root pressure (xylem sap exudation “bleeding”) during grafting. An experiment was conducted find the optimum irrigation regime for patch (in July) tongue March) on Juglans regia rootstock un­der three environmental co...

Enveloped viruses are released from infected cells after coalescence of viral components at cellular membranes and budding of membranes to release particles. For some negative-strand RNA viruses (e.g., vesicular stomatitis virus and Ebola virus), the viral matrix (M) protein contains all of the information needed for budding, since virus-like particles (VLPs) are efficiently released from cells...