GAL4 enhancer trap targeting of the Drosophila sex determination gene fruitless

The fru4 allele of the sex determination gene fruitless is induced by insertion of a P[lacZ,ry+] enhancer trap element. This insert also acts to disrupt expression of the fru P1 promoter derived male-specific proteins, consequently impairing male courtship behavior. fru4 maps less than 2 kb upstream of the fru P3 promoter, whose function is essential for viability. We replaced this insert with a GAL4 element, P[GAL4,w+], recovering two lines with insertions in opposite orientations at the locus, one of which demonstrated fru-specific mutant phenotypes. Reporter expression of these lines recapitulated that of P3- and P4-derived proteins which, when correlated with a developmental and tissue specific survey of fru promoters' activities, uncovered a previously unsuspected complexity of fru regulation. These novel fru alleles provide the tools for manipulation of fru-expressing cells, allowing the consequent effects to be related back to specific fru functions and the regulatory units controlling these activities.     

Mitochondrial DNA lineages of elite Ethiopian athletes

Previous studies have hypothesised that mitochondrial DNA (mtDNA) polymorphisms may influence aerobic performance. The matrilineal inheritance and accumulation of polymorphisms in mtDNA means that mtDNA haplogroups, characterised by key polymorphisms, are often represented at different frequencies in different populations. The present study aimed to compare the mtDNA haplogroup distribution of elite Ethiopian athletes relative to the general Ethiopian population. The haplogroup distribution of 76 endurance athletes (E), members of the Ethiopian national athletics team, was compared to 108 members of the general Ethiopian population (C). DNA was extracted from buccal swabs and haplogroups assigned by sequencing part of the hypervariable sequence (HVS-I), followed by analysis of key coding-region polymorphisms. A high proportion of African 'L' haplogroups was found in athletes and controls (C=53%; E=55%). Haplogroup distribution of endurance runners did not differ from that of C (P=0.63). Elite Ethiopian athletes are not a mitochondrially distinct group relative to the Ethiopian population. It appears that environment and, perhaps, polymorphisms in the nuclear genome are more important determinants of Ethiopian running success than mtDNA polymorphisms.     

Population structure and mating-type genes of Colletotrichum graminicola from Agrostis palustris

Eighty-seven isolates of Colletotrichum graminicola, mostly from Agrostis palustris, were collected in grass fields, most of which were in Ontario, Canada. Specific primers were designed to amplify the mating-type (MAT) genes and, among 35 isolates tested, all yielded a band of the expected size for MAT2. For six isolates, the MAT2 PCR products were sequenced and found to be similar to that reported for MAT2 of C. graminicola from maize. Based on 119 polymorphic bands from 10 random amplified polymorphic DNA primers, analyses of genetic distances were found to generally cluster isolates by host and geographic origin. Among 42 isolates from a grass field in Ontario, significant spatial autocorrelation was found to occur within a 20-m distance, implying that this is the effective propagule dispersal distance. Although clonal propagation was observed in the 87 isolates with 67 unique genotypes, the extent of genetic variation in local populations implies some occurrence of sexual or asexual recombination.     

Cytokine-induced coordinate expression of enzymes of prostaglandin biosynthesis and metabolism: 15-hydroxyprostaglandin dehydrogenase

The effects of pro-inflammatory cytokines on 15-hydroxyprostaglandin dehydrogenase (PGDH) expression and prostaglandin (PG) metabolizing activity were investigated in placental tissue. Treatment of trophoblast cells in primary culture with interleukin-1beta (IL-1beta) or tumour necrosis factor-alpha (TNF-alpha) resulted in decreased prostaglandin metabolizing activity. This was assessed both by determining the ratio of production of prostaglandins to their metabolites, and by Northern blot analysis of PGDH mRNA abundance. Dexamethasone had similar inhibitory effect. We hypothesize that proinflammatory cytokines act to enhance prostaglandin actions through coordinated effects on activities of enzymes of both prostaglandin biosynthesis and metabolism, perhaps in concert with effects on receptor function.     

Elevated T regulatory cells in long-term stable transplant tolerance in rhesus macaques induced by anti-CD3 immunotoxin and deoxyspergualin

Regulatory T cells (Tregs) are implicated in immune tolerance and are variably dependent on IL-10 for in vivo function. Brief peritransplant treatment of multiple nonhuman primates (NHP) with anti-CD3 immunotoxin and deoxyspergualin has induced stable (5-10 years) rejection-free tolerance to MHC-mismatched allografts, which associated with sustained elevations in serum IL-10. In this study, we demonstrate that resting and activated PBMC from long-term tolerant NHP recipients are biased to secrete high levels of IL-10, compared with normal NHP PBMC. Although IL-10-producing CD4+ Tregs (type 1 regulatory cells (TR1)/IL-10 Tregs) were undetectable (<0.5%) in normal rhesus monkeys, 7.5 +/- 1.7% of circulating CD4+ T cells of tolerant rhesus recipients expressed IL-10. In addition to this >15-fold increase in Tr1/IL-10 Tregs, the tolerant monkeys exhibited a nearly 3-fold increase in CD4+CD25+ Tregs, 8.1 +/- 3.0% of CD4 T cells vs 2.8 +/- 1.4% in normal cohorts (p < 0.02). The frequency of CD4+CD25+IL-10+ cells was elevated 5-fold in tolerant vs normal NHP (1.8 +/- 0.9% vs 0.4 +/- 0.2%). Rhesus CD4+CD25+ Tregs exhibited a memory phenotype, and expressed high levels of Foxp3 and CTLA-4 compared with CD4+CD25- T cells. Also, NHP CD4+CD25+ Tregs proliferated poorly after activation and suppressed proliferation of CD4+CD25- effector T cells, exhibiting regulatory properties similar to rodent and human CD4+CD25+ Tregs. Of note, depletion of CD4+CD25+ Tregs restored indirect pathway antidonor responses in tolerant NHP. Our study demonstrates an expanded presence of Treg populations in tolerant NHP recipients, suggesting that these adaptations may be involved in maintenance of stable tolerance.