Human replication protein A melts a DNA triple helix structure in a potent and specific manner.

Alternate DNA structures other than double-stranded B-form DNA can potentially impede cellular processes such as transcription and replication. The DNA triplex helix and G4 tetraplex structures that form by Hoogsteen hydrogen bonding are two examples of alternate DNA structures that can be a source of genomic instability. In this study, we have examined the ability of human replication protein A (RPA), a single-stranded DNA binding protein that is implicated in all facets of DNA metabolism, to destabilize DNA triplexes and tetraplexes.

FANCJ (BACH1) helicase forms DNA damage inducible foci with replication protein A and interacts physically and functionally with the single-stranded DNA-binding protein.

The BRCA1 associated C-terminal helicase (BACH1, designated FANCJ) is implicated in the chromosomal instability genetic disorder Fanconi anemia (FA) and hereditary breast cancer. A critical role of FANCJ helicase may be to restart replication as a component of downstream events that occur during the repair of DNA cross-links or double-strand breaks. We investigated the potential interaction of FANCJ with replication protein A (RPA), a single-stranded DNA-binding protein implicated in both DNA replication and repair.

Safety and efficacy of hydromorphone as an analgesic alternative to morphine in acute pain: a randomized clinical trial.

Study Objective: We compare a standard weight-based dose of intravenous hydromorphone (Dilaudid) to a standard weight-based dose of intravenous morphine in adults presenting to the ED with acute severe pain.

Methods: This was a prospective, randomized, double-blind, clinical trial conducted in an academic medical center. Of the 198 adult patients presenting to the ED with acute severe pain who were randomized to receive either intravenous hydromorphone at 0.

Intravenous morphine at 0.1 mg/kg is not effective for controlling severe acute pain in the majority of patients.

Study Objective: The objective was to quantify the analgesic effect of a dose of intravenous morphine, 0.1 mg/kg, to emergency department (ED) patients presenting in acute, severe pain.

Methods: This was a prospective convenience cohort of patients aged 21 to 65 years and presenting to an academic urban ED with acute, severe pain.

Physical and functional mapping of the replication protein a interaction domain of the werner and bloom syndrome helicases.

The single-stranded DNA-binding protein replication protein A (RPA) interacts with several human RecQ DNA helicases that have important roles in maintaining genomic stability; however, the mechanism for RPA stimulation of DNA unwinding is not well understood. To map regions of Werner syndrome helicase (WRN) that interact with RPA, yeast two-hybrid studies, WRN affinity pull-down experiments and enzyme-linked immunosorbent assays with purified recombinant WRN protein fragments were performed. The results indicated that WRN has two RPA binding sites, a high affinity N-terminal site, and a lower affinity C-terminal site.

p53 modulates RPA-dependent and RPA-independent WRN helicase activity.

Werner syndrome is a hereditary disorder characterized by the early onset of age-related symptoms, including cancer. The absence of a p53-WRN helicase interaction may disrupt the signal to direct S-phase cells into apoptosis for programmed cell death and contribute to the pronounced genomic instability and cancer predisposition in Werner syndrome cells. Results from coimmunoprecipitation studies indicate that WRN is associated with replication protein A (RPA) and p53 in vivo before and after treatment with the replication inhibitor hydroxyurea or gamma-irradiation that introduces DNA strand breaks.

Specific stimulation of human apurinic/apyrimidinic endonuclease by heat shock protein 70.

We previously demonstrated the stimulation of human apurinic/apyrimidinic endonuclease 1 (HAP1) by heat shock protein 70 (HSP70). In this work, we further defined the functional interaction between these proteins. Digestion of HSP70 by trypsin released 48 and 43 kDa amino terminal fragments that retained the ability to stimulate HAP1.