Intragenic DNA methylation: implications of this epigenetic mechanism for cancer research

Epigenetics is the study of all mechanisms that regulate gene transcription and genome stability that are maintained throughout the cell division, but do not include the DNA sequence itself. The best-studied epigenetic mechanism to date is DNA methylation, where methyl groups are added to the cytosine base within cytosine–guanine dinucleotides (CpG sites). CpGs are frequently clustered in high density (CpG islands (CGIs)) at the promoter of over half of all genes. Current knowledge of transcriptional regulation by DNA methylation centres on its role at the promoter where unmethylated CGIs are present at most actively transcribed genes, whereas hypermethylation of the promoter results in gene repression. Over the last 5 years, research has gradually incorporated a broader understanding that methylation patterns across the gene (so-called intragenic or gene body methylation) may have a role in transcriptional regulation and efficiency. Numerous genome-wide DNA methylation profiling studies now support this notion, although whether DNA methylation patterns are a cause or consequence of other regulatory mechanisms is not yet clear. This review will examine the evidence for the function of intragenic methylation in gene transcription, and discuss the significance of this in carcinogenesis and for the future use of therapies targeted against DNA methylation

The S phase checkpoint promotes the Smc5/6 complex dependent SUMOylation of Pol2, the catalytic subunit of DNA polymerase ε

Replication fork stalling and accumulation of single-stranded DNA trigger the S phase checkpoint, a signalling cascade that, in budding yeast, leads to the activation of the Rad53 kinase. Rad53 is essential in maintaining cell viability, but its targets of regulation are still partially unknown. Here we show that Rad53 drives the hyper-SUMOylation of Pol2, the catalytic subunit of DNA polymerase ε, principally following replication forks stalling induced by nucleotide depletion. Pol2 is the main target of SUMOylation within the replisome and its modification requires the SUMO-ligase Mms21, a subunit of the Smc5/6 complex. Moreover, the Smc5/6 complex co-purifies with Pol ε, independently of other replisome components. Finally, we map Pol2 SUMOylation to a single site within the N-terminal catalytic domain and identify a SUMO-interacting motif at the C-terminus of Pol2. These data suggest that the S phase checkpoint regulate Pol ε during replication stress through Pol2 SUMOylation and SUMO-binding abilit

General flowering in the climax rain forests of South-east Asia

ABSTRACTThe general flowering of lowland dipterocarp forests of South-east Asia is a unique phenomenon that occurs intermittently, sometimes many years apart, and may be widespread throughout the region or sporadic. During a general flowering a very large number of tree families, including the well-known Dipterocarpaceae, flower and fruit exceptionally heavily. The huge pulse of flowering is echoed by an apparent explosion in the number of pollinators, and this is further augmented by migration of pollinators from the forest fringes. The huge demand for pollinators seems to be solved among several dipterocarps through utilization of tiny, fast breeding, floral-feeding insects such as thrips and hoppers. Competition for pollinators is further reduced through development of sequential flowering among several groups of trees that share similar pollinators. The resulting massive general fruiting seems to contribute to a heightened level of faunal activity and numbers. This long-intervalled flowering and fruiting phenology which dominates these lowland dipterocarp forests may have partly contributed to the lowered animal biomass frequently alluded to when these forests are compared with neotropical forests.</jats:p

A review of dipterocarps: taxonomy, ecology and silviculture

Dipterocarps are one of the best known and commercially important groups of tropical trees. They preside over some of the most magnificent forest formations in the world. Exploitation of dipterocarp-dominated tropical rain forests has expanded rapidly in the past 20 years. Efforts to develop and implement sustainable management practices are being intensified and there is a pressing need for high quality information on which to base management decisions and reorient research. This book is a critical compilation of the results of research spanning 150 years on the taxonomy, ecology, silviculture and non-timber forest products of these trees. The 13 authors are internationally recognised as specialists in their fields, and the 10 chapters provide comprehensive digests of information and identification of priority research needs

Rattan cultivation: achievements, problems and prospects. An international consultation of experts for the project: conservation, genetic improvement, and silviculture of rattan in South-East Asia

Rattan cultivation: achievements, problems and prospects. An international consultation of experts for the project: conservation, genetic improvement, and silviculture of rattan in South-East Asia . Meeting of Rattan Cultivation - Achievements, Problems and Prospect

FORSPA initiative for rehabilitation of tropical forests in Asia-Pacific region

Tropical forests of the Asia-Pacific region are the most heavily threatened from high population density and rapid economic growth. Extensive forest areas have become degraded as a result of over-exploitation and poor management. Unless these degraded forests are rehabilitated, they will come under pressure from other land uses. Recognising this, the Forest Research Support Programme for Asia and the Pacific (FORSPSA) of FAO initiated a Rehabilitation Programme and has started to set up a series of model plots of about 100 ha in each of the eco-climatic regions of Asia and the Pacific. Unproductive second growth forest areas will be rehabilitated using indigenous species of commercial value and techniques that are most familiar locally and well-proven. The plots will be model areas for research and training extend the methods to other parts of the region with similar ecological conditions. These plots, which are accessible to international scientists, will be maintained for long enough to achieve and extend results. To further enhance the rehabilitation work, the group of scientists and forest managers will be soon linked through the Asia Pacific Forest Rehabilitation Network (APFReN). This will link together scientists and managers engaged in rehabilitation work to share experiences and solve problems. The Rehabilitation Programme will include training courses, workshops and publication of literature on forest rehabilitation issues