Varying strength of selection contributes to the intragenomic diversity of rRNA genes.

Ribosome biogenesis in eukaryotes is supported by hundreds of ribosomal RNA (rRNA) gene copies that are encoded in the ribosomal DNA (rDNA). The multiple copies of rRNA genes are thought to have low sequence diversity within one species. Here, we present species-wide rDNA sequence analysis in Saccharomyces cerevisiae that challenges this view.

[Reconstruction of caval veins].

Objective: To study the possibilities and results of reconstruction of caval veins.

Material And Methods: We analyzed the results of reconstruction of caval veins in 31 patients (19 men and 12 women) including superior vena cava (SVC) in 5 cases and inferior vena cava (IVC) in 26 cases. Penetrating wounds with vascular damage were found in 8 patients.

Histone Tails Promote PARP1-Dependent Structural Rearrangements in Nucleosomes.

PARP 1 alters the wrapping of nucleosomal DNA on the histone octamer, thereby modulating the accessibility of different genome sites to nuclear protein factors. Here, we show that non-structured histone tails are involved in the PARP1-induced structural rearrangements in nucleosomes, facilitate and stabilize them, but do not affect the enzymatic activity of PARP1.

Unfolding of core nucleosomes by PARP-1 revealed by spFRET microscopy.

DNA accessibility to various protein complexes is essential for various processes in the cell and is affected by nucleosome structure and dynamics. Protein factor PARP-1 (poly(ADP-ribose)polymerase 1) increases the accessibility of DNA in chromatin to repair proteins and transcriptional machinery, but the mechanism and extent of this chromatin reorganization are unknown. Here we report on the effects of PARP-1 on single nucleosomes revealed by spFRET (single-particle Förster Resonance Energy Transfer) microscopy.