Interactions of the Human MCM-BP Protein with MCM Complex Components and Dbf4

MCM-BP was discovered as a protein that co-purified from human cells with MCM proteins 3 through 7; results which were recapitulated in frogs, yeast and plants. Evidence in all of these organisms supports an important role for MCM-BP in DNA replication, including contributions to MCM complex unloading. However the mechanisms by which MCM-BP functions and associates with MCM complexes are not well understood. Here we show that human MCM-BP is capable of interacting with individual MCM proteins 2 through 7 when co-expressed in insect cells and can greatly increase the recovery of some recombinant MCM proteins. Glycerol gradient sedimentation analysis indicated that MCM-BP interacts most strongly with MCM4 and MCM7. Similar gradient analyses of human cell lysates showed that only a small amount of MCM-BP overlapped with the migration of MCM complexes and that MCM complexes were disrupted by exogenous MCM-BP. In addition, large complexes containing MCM-BP and MCM proteins were detected at mid to late S phase, suggesting that the formation of specific MCM-BP complexes is cell cycle regulated. We also identified an interaction between MCM-BP and the Dbf4 regulatory component of the DDK kinase in both yeast 2-hybrid and insect cell co-expression assays, and this interaction was verified by co-immunoprecipitation of endogenous proteins from human cells. In vitro kinase assays showed that MCM-BP was not a substrate for DDK but could inhibit DDK phosphorylation of MCM4,6,7 within MCM4,6,7 or MCM2-7 complexes, with little effect on DDK phosphorylation of MCM2. Since DDK is known to activate DNA replication through phosphorylation of these MCM proteins, our results suggest that MCM-BP may affect DNA replication in part by regulating MCM phosphorylation by DDK

Convective self-aggregation in numerical simulations: a review

Organized convection in the Tropics occurs across a range of spatial and temporal scales and strongly influences cloud cover and humidity. One mode of organization found is “self-aggregation”, in which moist convection spontaneously organizes into one or several isolated clusters despite spatially homogeneous boundary conditions and forcing. Self-aggregation is driven by interactions between clouds, moisture, radiation, surface fluxes, and circulation, and occurs in a wide variety of idealized simulations of radiative-convective equilibrium. Here we provide a review of convective self-aggregation in numerical simulations, including its character, causes, and effects. We describe the evolution of self-aggregation including its time and length scales and the physical mechanisms leading to its triggering and maintenance, and we also discuss possible links to climate and climate change

ORAL-ADMINISTRATION OF BCG AS AN ADJUVANT TO SURGICAL TREATMENT OF CARCINOMA OF THE BRONCHUS

A controlled clinical trial of the value of bacille Calmette--Guérin (BCG) vaccine given orally to patients with resectable carcinoma of the lung was conducted in 18 centres across Canada. A total of 308 patients were included in the analysis, 155 in the BCG group and 153 in the control group. The two groups were similar at the time of admission to the trial. BCG (120 mg) was given orally at weekly intervals for 1 month, every 2 weeks up to 3 months and then every 3 months until the total duration of therapy was 18 months. Over a 3- to 5-year follow-up period after the operation there was no difference in survival between the two groups, the proportion alive at 2 years being 61% in the BCG group and 58% in the control group. There was also no evidence of differences in the time to the detection of recurrent or metastatic disease or in the distribution of such disease. An analysis of prognostic factors confirmed the poor survival associated with histologically confirmed lymph node involvement. It may be concluded that no favourable effect from the oral administration of BCG was demonstrated