Identification of the P-TEFb complex-interacting domain of Brd4 as an inhibitor of HIV-1 replication by functional cDNA library screening in MT-4 cells

We conducted a phenotypic cDNA screening using a T cell line-based assay to identify human genes that render cells resistant to human immunodeficiency virus type 1 (HIV-1). We isolated potential HIV-1 resistance genes, including the carboxy terminal domain (CTD) of bromodomain-containing protein 4 (Brd4). Expression of GFP-Brd4-CTD was tolerated in MT-4 and Jurkat cells in which HIV-1 replication was markedly inhibited. We provide direct experimental data demonstrating that Brd4-CTD serves as a specific inhibitor of HIV-1 replication in T cells. Our method is a powerful tool for the identification of host factors that regulate HIV-1 replication in T cells.     

Genetic Population Structure of Chum Salmon in the Pacific Rim Inferred from Mitochondrial DNA Sequence Variation

We examined the genetic population structure of chum salmon, Oncorhynchus keta, in the Pacific Rim using mitochondrial (mt) DNA analysis. Nucleotide sequence analysis of about 500 bp in the variable portion of the 5′ end of the mtDNA control region revealed 20 variable nucleotide sites, which defined 30 haplotypes of three genealogical clades (A, B, and C), in more than 2,100 individuals of 48 populations from Japan (16), Korea (1), Russia (10), and North America (21 from Alaska, British Columbia, and Washington). The observed haplotypes were mostly associated with geographic regions, in that clade A and C haplotypes characterized Asian populations and clade B haplotypes distinguished North American populations. The haplotype diversity was highest in the Japanese populations, suggesting a greater genetic variation in the populations of Japan than those of Russia and North America. The analysis of molecular variance and contingency χ² tests demonstrated strong structuring among the three geographic groups of populations and weak to moderate structuring within Japanese and North American populations. These results suggest that the observed geographic pattern might be influenced primarily by historic expansions or colonizations and secondarily by low or restricted gene flow between local groups within regions. In addition to the analysis of population structure, mtDNA data may be useful for constructing a baseline for stock identification of mixed populations of high seas chum salmon.     

Molecular cloning and characterization of coclaurine N-methyltransferase from cultured cells of Coptis japonica.

S-adenosyl-L-methionine:coclaurine N-methyltransferase (CNMT) converts coclaurine to N-methylcoclaurine in isoquinoline alkaloid biosynthesis. The N-terminal amino acid sequence of Coptis CNMT was used to amplify the corresponding cDNA fragment and later to isolate full-length cDNA using 5'- and 3'-rapid amplification of cDNA ends (RACE). The nucleotide sequence and predicted amino acid sequence showed that the cDNA encoded 358 amino acids, which contained a putative S-adenosyl-L-methionine binding domain and showed relatively high homology to tomato phosphoethanolamine-N-methyltransferase. A recombinant protein was expressed in Escherichia coli, and its CNMT activity was confirmed. Recombinant CNMT was purified to homogeneity, and enzymological characterization confirmed that Coptis CNMT has quite broad substrate specificity, i.e. not only for 6-O-methylnorlaudanosoline and norreticuline but also for 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline. The evolution of N-methyltransferases in secondary metabolism is discussed based on sequence similarity.     

Ranges of diurnal variation and the pattern of body temperature, blood pressure and heart rate in laboratory beagle dogs.

Ranges in diurnal variation and the patterns of body temperature (T), blood pressure (BP), heart rate (HR) and locomotor activity (LA) in 61 laboratory beagle dogs were analyzed using a telemetry system. Body temperature, BP, HR and LA increased remarkably at feeding time. Locomotor activity increased sporadically during the other periods. Body temperature was maintained at the higher value after feeding but had decreased by 0.2 C by early the next morning. Blood pressure fell to a lower value after feeding but had increased by 2.8% by early the next morning. Heart rate decreased progressively after feeding and was 14.5% lower the next morning. This study determined that in laboratory beagles the ranges of diurnal variation and patterns of T, BP and HR are significantly different from those reported in humans and rodents, and that over 24 hr these physiological changes were associated with their sporadic wake-sleep cycles of the dogs.     

A comment on the evaluation of equilibrium constants for alpha-tocopherol interactions with fatty acids by absorbance in the ultraviolet region

This paper comments on the evaluation of Erin and co-workers (Biochim. Biophys. Acta 774 (1984) 96-102) of equilibrium constants for alpha-tocopherol interactions with fatty acids on the basis of the changes of absorbance in a 200 nm ultraviolet region. It is concluded that the ultraviolet method is inadequate because it is affected by absorption in that region of the solvent, ethanol and fatty acids which they used.