Low blood pressure in endothelial cell-specific endothelin 1 knockout mice.

Endothelin (ET) 1 is a potent vasoconstrictor peptide produced by vascular endothelial cells and implicated in various pathophysiologic states involving abnormal vascular tone. Homozygous ET-1 null mice have craniofacial and cardiac malformations that lead to neonatal death. To study the role of ET-1 in adult vascular physiology, we generated a mouse strain (ET-1(flox/flox);Tie2-Cre mice) in which ET-1 is disrupted specifically in endothelial cells.

Accumulation of sumoylated Rad52 in checkpoint mutants perturbed in DNA replication.

Checkpoints are cellular surveillance and signaling pathways that regulate responses to DNA damage and perturbations of DNA replication. Here we show that high levels of sumoylated Rad52 are present in the mec1 sml1 and rad53 sml1 checkpoint mutants exposed to DNA-damaging agents such as methyl methanesulfonate (MMS) or the DNA replication inhibitor hydroxyurea (HU). The kinase-defective mutant rad53-K227A also showed high levels of Rad52 sumoylation.

Nuclear localization of Rad52 is pre-requisite for its sumoylation.

In Saccharomyces cerevisiae, Rad52 plays major roles in several types of homologous recombination. Here, we found that rad52-K200R mutation greatly reduced sumoylation of Rad52. The rad52-K200R mutant exhibited defects in various types of recombination, such as intrachromosomal recombination and mating-type switching.

Rad52 sumoylation and its involvement in the efficient induction of homologous recombination.

The protein Rad52 is a key player in various types of homologous recombination and is essential to maintenance of genomic integrity. Although evidence indicates that Rad52 is modified by SUMO, the physiological relevance of this sumoylation remains unclear. Here, we identify the conditions under which Rad52 sumoylation is induced, and clarify the role of this modification in homologous recombination.

Ctf18 is required for homologous recombination-mediated double-strand break repair.

The efficient repair of double-strand breaks (DSBs) is crucial in maintaining genomic integrity. Sister chromatid cohesion is important for not only faithful chromosome segregation but also for proper DSB repair. During DSB repair, the Smc1-Smc3 cohesin complex is loaded onto chromatin around the DSB to support recombination-mediated DSB repair.

A neuropeptide ligand of the G protein-coupled receptor GPR103 regulates feeding, behavioral arousal, and blood pressure in mice.

Here, we report the isolation and characterization of an endogenous peptide ligand of GPR103 from rat brains. The purified peptide was found to be the 43-residue RF-amide peptide QRFP. We also describe two mouse homologues of human GPR103, termed mouse GPR103A and GPR103B.

Protective properties of neoechinulin A against SIN-1-induced neuronal cell death.

Peroxynitrite (ONOO-) is thought to be involved in the neurodegenerative process. To screen for neuroprotective compounds against ONOO- -induced cell death, we developed 96-well based assay procedures for measuring surviving cell numbers under oxidative stress caused by 3-(4-morpholinyl) sydnonimine hydrochloride (SIN-1), a generator of ONOO-, and sodium N,N-dietyldithiocarbamate trihydrate (DDC), an inhibitor of Cu/Zn superoxide (O2-) dismutase. Using these procedures, we obtained a microbial metabolite that rescued primary neuronal cells from SIN-1-induced damage, but not from DDC-induced damage.

Dissociation of DNA polymerase alpha-primase complex during meiosis in Coprinus cinereus.

Previously, the activity of DNA polymerase alpha was found in the meiotic prophase I including non-S phase stages, in the basidiomycetes, Coprinus cinereus. To study DNA polymerase alpha during meiosis, we cloned cDNAs for the C. cinereus DNA polymerase alpha catalytic subunit (p140) and C.

Attenuated defense response and low basal blood pressure in orexin knockout mice.

The perifornical area of the hypothalamus has been known as the center for the defense response, or "fight or flight" response, which is characterized by a concomitant rise in arterial blood pressure (AP), heart rate (HR), and respiratory frequency (Rf). We examined whether orexin, a recently identified hypothalamic neuropeptide, contributes to the defense response and basal cardiovascular regulation using orexin knockout mice. Microinjection of a GABA-A receptor antagonist, bicuculline methiodide (0.

Vascular endothelin-B receptor system in vivo plays a favorable inhibitory role in vascular remodeling after injury revealed by endothelin-B receptor-knockout mice.

Background: Two subtypes of endothelin (ET) receptors, ET(A) and ET(B), are distributed in vascular smooth muscle cells to cause contraction and proliferation. Vascular endothelial cells express only ET(B) receptors, which cause NO release. Although ET(A) receptor blockade is reported to be effective in ameliorating vascular remodeling, there is no report on the long-term effect of ET(B) receptor blockade on vascular remodeling after injury.

Assay-based quantitative analysis of PC12 cell differentiation.

Differentiation of PC12 cells has been quantified by measurement of neurite length. However, this procedure is not suitable for large numbers of samples, for example in 96-well tissue culture plates. For this reason, we established three simple and quantitative methods for nerve growth factor-induced differentiation of PC12 cells cultured in 96-well plates.