Enoyl-acyl carrier protein reductase: Characterization of a housekeeping gene involved in storage lpid synthesis in seeds of Arabidopsis and ot

The fatty acid synthetase (FAS) system in plants and bacteria consists of a type II FAS complex assembled from different monofunctional polypeptides catalysing the individual reactions involved in each cycle of the de novo synthesis of fatty acids. Enoyl-ACP reductase (EC 1.3.1.9) plays the determinant role in completing cycles of de novo fatty acid biosynthesis, by removing a trans-unsaturated double bond to give a saturated acyl-ACP. Genetic analyses revealed that the NADH-specific enoyl-ACP reductase (ENR) is encoded by a single gene in different plant species like Petunia hybrida and Arabidopsis thaliana, whereas the allotetraploid Nicotiana tabacum contains two enr encoding genes. This implies that enhanced expression of enr genes, e.g. during seed development, is due to a modification of the expression level of a housekeeping gene. Besides a high degree of homology observed within the exon and intron sequences of the analysed enr genes, the positions of the introns and exons were also found to be conserved. Other similarities are the presence of a large intron in the 5' untranslated leader sequence of the genes as well as a conserved 5' GC intron splice site. Experiments have been performed to analyse the functional importance of this 5' GC splice site with regard to the regulation of enr expression. Homology between the 5' flanking region of both tobacco enr genes, enr-T1 and enr-T2, appears to be limited to short stretches of conserved sequences which are frequently interrupted by insertions of different (retro) transposon-like elements in the promoter of enr-T2. By contrast, the arabidopsis enr promoter region does not show any significant homology when compared with similar regions of the tobacco enr genes

The complete nucleotide sequence of tobacco necrosis virus strain D

The complete sequence of the RNA genome of tobacco necrosis virus strain D (TNV-D) consisting of 3759 nucleotides has been determined. The positive strand contains five open reading frames (ORFs). The 5'proximal ORF encodes a 22K protein terminating with an amber codon which may be read through to produce a 82K protein (p82). Two small centrally located ORFs each encode two out-of-frame 7K proteins (p7a and p7b). The 3'-proximal ORF encodes the 29K coat protein (CP), the N terminus of which has been sequenced directly. The genomic organization of TNVD is very similar to that of TNV-A but differs in the placement of the p7a ORF, which does not overlap the p82 ORF in TNV-D, and in the absence of an ORF downstream of the CP gene in TNV-D. The p82 ORF shows extensive sequence similarity with the putative polymerases of the carmovirus group. This ORF is also as closely related to the corresponding ORF of TNV-A as it is to the corresponding ORF of the tombusvirus cucumber necrosis virus. The amino acid sequence of the TNV-D CP gene is similar to both the TNV-A and southern bean mosaic virus CP genes. Of the two p7 ORFs, p7a exhibits amino acid sequence similarity with corresponding proteins from TNV-A, melon necrotic spot virus, carnation mottle virus, turnip crinkle virus and maize chlorotic mottle virus, whereas the p7b ORF appears to be unique to TNV-A and TNV-D. Only the 3'-terminal three nucleotides of TNV-D genomic RNA are identical to the 3'-terminal nucleotides of the TNV satellite virus.Peer reviewe

Evaluation of an in vitro model of androgen ablation and identification of the androgen responsive proteome in LNCaP cells

Proteins responsive to androgen and anti-androgen may be involved in the development and progression of prostate cancer and the ultimate failure of androgen-ablation therapy. These proteins represent potential diagnostic and therapeutic targets for improved management of prostate cancer. We have investigated the effect of androgen (R1881) and anti-androgen (bicalutamide) on the androgen-responsive prostate cancer LNCaP cell line using a quantitative gel-based proteomic approach. Prior to analysis, the in vitro system was evaluated for reproducibility and validated by appropriate molecular responses to treatment. Six replicate samples were independently generated and analysed by 2-D DIGE. According to strict statistical criteria, 197 spots were differentially expressed, of which we have successfully identified 165 spots corresponding to 125 distinct proteins. Following androgen supplementation, 108 spots (68 proteins) were increased and 57 spots (39 proteins) were decreased. Essentially no difference was observed between control and anti-androgen-treated samples, confirming the absence of off-target effects of bicalutamide. Identified proteins were involved in diverse processes including the stress response and intracellular signalling. The potential contribution to disease of these processes and identified constituent proteins are discussed. This rigorous, statistically supported study of androgen responses has provided a number of potential candidates for development as diagnostic/prognostic markers and drug targets