Characterisation of the GRAF gene promoter and its methylation in patients with acute myeloid leukaemia and myelodysplastic syndrome

We report the isolation of the 5′ flanking region of GRAF (GTPase regulator associated with the focal adhesion kinase), previously described as a putative tumour suppressor gene of acute myelogenous leukaemia and myelodysplastic syndrome, and demonstrate its promoter activity in reporter gene assays. Two putative protein-binding sites are identified of which one was sensitive to CpG methylation. The suppressed GRAF expression could be restored in leukaemia cell lines by treatment with a demethylating agent and an inhibitor of histone deacetylases. In contrast to normal tissues, which tested negative for GRAF promoter methylation, 11 of 29 (38%) bone marrow samples from patients with acute myeloid leukaemia or myelodysplastic syndrome were positive

Biosynthesis of monoterpene hydrocarbons by isolated chromoplasts from daffodil flowers

Incubation studies using [1-14C]isopentenyl diphosphate and [12H2]isopentenyl diphosphate as substrates revealed that isolated chromoplasts from flowers of Narcissus pseudonarcissus L. are able to synthesize monoterpene hydrocarbons and linalool in hig

Electron transport pathways in isolated chromoplasts from Narcissus pseudonarcissus L

International audienceDuring daffodilflower development,chloroplasts differentiate into photosynthetically inactive chromoplasts, which have lostfunctional photosynthetic reaction centers. Chromoplasts exhibit a respiratory activity reducing oxygen to water and generating ATP. Immunoblots revealed the presence of the plastid terminal oxidase(PTOX), the NAD(P)H dehydrogenase (NDH) complex, the cytochrome b6fcomplex, ATP synthase and several isoforms of ferredoxin-NADP+oxidoreductase (FNR) and of ferredoxin (Fd). Fluorescence spectroscopy allowed the detection of chlorophyll a in the cytochrome b6fcomplex. Here we characterize the electron transport pathway of chromorespiration by using specific inhibitors forthe NDH complex, the cytochrome b6fcomplex, FNR and redox-inactive Fd in which the iron was replaced by gallium. Our data suggest anelectron flowvia twoseparatepathways, both reducing plastoquinone and using PTOX as oxidase. The first oxidizes NADPH via FNR, Fd,and cytochrome bh of the cytochrome b6fcomplex and does not result in the pumpingofprotons across the membrane. In the second,electron transport takes place via the NDH complex using preferentially NADH but also NADPH as electron donor. FNR and Fd are not involved in this pathway. The NDH-complex is responsible for the generation of the proton gradient. We propose a new model for chromorespiration which may also be relevant for the understanding of chlororespiration and for the characterization of the electron input from Fd to the cytochrome b6fcomplex during cyclic electron transport in chloroplasts