Genetic analysis of thirty-three platelet polypeptides detected in two-dimensional polyacrylamide gels.

Two-dimensional gel electrophoresis followed by silver-staining was utilized to visualize platelet polypeptides for genetic analysis. A subset of 33 polypeptides that were most suited for scoring was selected. Families consisting of father-mother-child trios were studied. Thirty-six polypeptides of a total of 1,413 scored in children's gels exhibited the combination of a normal and a variant polypeptide. The observed index of heterozygosity of 2.55% is comparable to our previously reported findings for red cell proteins.     

Effects of arginine-vasopressin and ACTH 4-10 on acquisition of active avoidance response in rats with alcohol pretreatment in prenatal and adult age

Alcohol administration in drinking water to mother rats during gestation resulted in a permanent learning deficit of the offspring when behavioural reactions were tested in active avoidance conditioned reflex situation in adult age. A similar deficit of learning capacity was observed in adult rats following alcohol administration for two weeks; the acquisition of active avoidance response was tested later. Administration of arginine-vasopressin and ACTH 4-10 during behavioural test led to a significant improvement of learning ability of the animals pretreated with alcohol. The observations indicate that the ethanol-induced deficit of learning capacity involves peptidergic mechanisms and the behavioural manifestations following chronic alcohol treatment are not irreversible processes.     

BRCA1 maps proximal to D17S579 on chromosome 17q21 by genetic analysis

Previous studies have demonstrated linkage between early-onset breast cancer and ovarian cancer and genetic markers on chromosome 17q21. These markers define the location of a gene (BRCA1) which appears to be inherited as an autosomal dominant susceptibility allele. We analyzed five families with multiple affected individuals for evidence of linkage to the BRCA1 region. Two of the five families appear to be linked to BRCA1. One apparently linked family contains critical recombinants, suggesting that the gene is proximal to the marker D17S579 (Mfd188). These findings are consistent with the maximum-likelihood position estimated by the Breast Cancer Linkage Consortium and with recombination events detected in other linked families. Linkage analysis was greatly aided by PCR-based analysis of paraffin-embedded normal breast tissue from deceased family members, demonstrating the feasibility and importance of this approach. One of the two families with evidence of linkage between breast cancer and genetic markers flanking BRCA1 represents the first such family of African-American descent to be reported in detail.     

Genetic Polymorphism of Experimentally Produced Forms of Arterial Hypertension

Russian Journal of Genetics - The paper analyzes the distribution of polymorphic loci in rats of different hypertensive strains. When analyzing the transcribed loci of ISIAH rats and the...     

Persistent replication of hepatitis C virus replicons expressing the beta-lactamase reporter in subpopulations of highly permissive Huh7 cells

Progress toward development of better therapies for the treatment of hepatitis C virus (HCV) infection has been hampered by poor understanding of HCV biology and the lack of biological assays suitable for drug screening. Here we describe a powerful HCV replication system that employs HCV replicons expressing the beta-lactamase reporter (bla replicons) and subpopulations of Huh7 cells that are more permissive (or "enhanced") to HCV replication than na?ve Huh7 cells. Enhanced cells represent a small fraction of permissive cells present among na?ve Huh7 cells that is enriched during selection with replicons expressing the neomycin phosphotransferase gene (neo replicons). The level of permissiveness of cell lines harboring neo replicons can vary greatly, and the enhanced phenotype is usually revealed upon removal of the neo replicon with inhibitors of HCV replication. Replicon removal is responsible for increased permissiveness, since this effect could be reproduced either with alpha interferon or with an HCV NS5B inhibitor. Moreover, adaptive mutations present in the replicon genome used during selection do not influence the permissiveness of the resulting enhanced-cell population, suggesting that the mechanisms governing the permissiveness of enhanced cells are independent from viral adaptation. Because the beta-lactamase reporter allows simultaneous quantitation of replicon-harboring cells and reporter activity, it was possible to investigate the relationship between genome replication activity and the frequency with which transfected genomes can establish persistent replication. Our study demonstrates that differences in the replication potential of the viral genome are manifested primarily in the frequency with which persistent replication is established but modestly affect the number of replicons observed per replicon-harboring cell. Replicon copy number was found to vary over a narrow range that may be defined by a minimal number required for persistent maintenance and a maximum that is limited by the availability of essential host factors.     

Identification of a key determinant of hepatitis C virus cell culture adaptation in domain II of NS3 helicase

Efficient replication of hepatitis C virus (HCV) replicons in cell culture is associated with specific sequences not generally observed in vivo. These cell culture adaptive mutations dramatically increase the frequency with which replication is established in vitro. However, replicons derived from HCV isolates that have been shown to replicate in chimpanzees do not replicate in cell culture even when these adaptive mutations are introduced. To better understand this apparent paradox, we performed a gain-of-function screen to identify sequences that could confer cell culture replication competence to replicons derived from chimpanzee infectious HCV isolates. We found that residue 470 in domain II of the NS3 helicase is a critical determinant in cell culture adaptation. Substitutions in residue 470 when combined with the NS5A-S232I adaptive mutation are both necessary and sufficient to confer cell culture replication to otherwise inactive replicons, including those derived from genotype 1b HCV-BK and genotype 1a HCV-H77 isolates. The specific substitution at residue 470 required for replication is context-dependent, with R470M and P470L being optimal for the activity of HCV-BK and HCV-H77 replicons, respectively. Together these data indicate that mutations in the NS3 helicase domain II act in concert with previously identified adaptive mutations and predict that introduction of compatible residues at these positions can confer cell culture replication activity to diverse HCV isolates.