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Regulation of stress-responsive genes represent one of the best examples of gene induction, and the relevance and involvement of different regulators may change for a given gene depending on the challenging stimulus. The HSP12 gene is induced by very different stimuli; however, the molecular response to stress has been characterized in detail only for heat shock treatments. In this study, we aimed to verify whether the regulation of transcription induced by oxidative stress utilizes the same epigenetic solutions as those employed in the heat shock response. We also monitored HSP12 induction by employing spermidine, a known acetyltransferase inhibitor, and observed an oxidative stress that synergizes with spermidine treatment. Our data show that during transcriptional response to [H.sub.2][O.sub.2], histone acetylation and chromatin remodeling occur. However, when the relevance of Gcn5p to these processes was studied, we observed that induction of transcription is GCN5-dependent, and this does not rely on histone acetylation by Gcn5p despite its HAT activity. Chromatin remodeling accompanying gene activation is GCN5 dependent. Thus, GCN5 controls HSP12 transcription after [H.sub.2][O.sub.2] treatment by allowing chromatin remodeling, and it is only partially involved in HSP12 histone acetylation regardless of its HAT activity. Key words: HSP12, chromatin remodeling, GCN5, nucleosome occupancy. La régulation des gènes sensibles au stress représente l'un des meilleurs exemples d'induction génique, et la pertinence et l'implication des différents régulateurs peuvent changer pour un gène donné selon le stimulus. Le gene HSP12 est induit par des stimuli très différents, mais la réponse moléculaire au stress n'a été caractérisée en détail que pour les traitements par choc thermique. Dans ce travail, les auteurs désirent vérifier si la régulation de la transcription induite par le stress oxydant utilise les mêmes mécanismes épigénétiques par rapport à ceux observés dans la réponse au choc thermique. Ils ont aussi suivi l'induction de HSP12 en utilisant la spermidine, un inhibiteur connu d'acétyltransférase et observé un stress oxydant qui agit en synergie avec le traitement à la spermidine. Ces données montrent que pendant la réponse transcriptionnelle au [H.sub.2][O.sub.2], l'acétylation des histones et le remodelage de la chromatine se produisent. Cependant, lorsque l'implication de Gcn5p sur ces processus a été étudiée, ils ont observé que l'induction de la transcription est dépendante de GCN5 et que cela ne repose pas sur l'acétylation des histones par Gcn5p malgré son activité HAT. Le remodelage de la chromatine accompagnant l'activation des gènes est plutôt dépendant de GCN5. Ainsi, GCN5 contrôle la transcription de HSP12 après un traitement au [H.sub.2][O.sub.2] en permettant le remodelage de la chromatine et il n'est que partiellement impliqué dans l'acétylation des histones de HSP12 malgré son activité HAT. [Traduit par la Rédaction] Mots-clés : HSP12, remodelage de la chromatine, GCN5, occupation du nucleosome., Introduction Oxidative stress, pH changes, alterations in nutrient amounts, temperature, or osmolarity changes, all of which induce an adaptive response in any cell typeto achieve maximal cell survival. Thus, much [...]

Leg Length Discrepancy (LLD) is very often associated to Low Back Pain (LBP), but still controversial is the use of underfoot wedge correction (heel rise) to re-balance pelvis and trunk posture. In a review of our last 5 years clinical activity we observed that more than 70% out of 300 LBP patients presented a LLD. In more than 80 % we ascertained, via Baropodography, the presence of underfoot asymmetric load, during standing. More durable therapy recovery effect has been observed when LLD correction had been adopted. These reasons led us to start a study to assess if a Full 3D multifactorial Posture evaluation approach, by means of Opto-electronic device associated to foot pressure maps recording, was able to quantitatively discriminate the clinically observed phenomena. On a 94 LBP (av. age 46.3±16 Y range 15-82 Y) patients sample, 83 (88%) have been found to improve posture when LLD was corrected. The 94 patients showed a mean lower limb discrepancy of μ=8±3.2mm associated to a mean scoliotic lumbar curve μ=10.5°±5.1° Cobb (frontal plane), mean Spinal offset μ=6.6±4.9mm and mean Global offset 10.7±8.8mm. The applied paired t-test comparison (indifferent vs. corrected orthostasis) showed significant (p < 0.05) postural improvements could be obtained in the whole or in a part of the considered parameters, both in rebalancing and in spine deformities reduction after the application of suitable under-foot wedge. The joint 3D opto-electronic and foot pressure map approach proved to be effective to control several clinical parameters with statistical significance. [ABSTRACT FROM AUTHOR]

The aetiological aspects as well as postural attitude implications represent an open question in scoliosis evaluation and treatment. Leg length discrepancy (LLD) is often recognised in scoliotic patients, but surprisingly still controversial is the use of underfoot wedge corrections in order to compensate pelvis tilt. In fact, literature reports conflicting results on the efficacy of LLD equalization also given the argued uncertainty of LLD clinical assessment and limitations related to X-ray measurements. Moreover concern is about anatomic and functional LLD and associated estimation of the pelvic torsion. In such a topic, a significant helpful tool has been demonstrated to be 3D kinematic optoelectronic measurements and other useful data obtained from force platforms and/or baropodographic systems. 135 (94.4%) out of 143 Scoliotic patients sample (av. age 16.4±10.2 Y range 4-66 Y), have been found to improve posture when LLD was corrected. The 143 patients showed a mean lower limb discrepancy of μ=10.2±5.2mm associated to a mean main scoliotic curve μ=16.4°±9.4° Cobb (frontal plane), mean Spinal offset μ=7.5±5.5mm and mean Global offset μ=10.1±7.1mm. The applied paired t-test comparison (indifferent vs. corrected orthostasis) showed significant (p < 0.05) postural improvements could be obtained in the whole or in a part of the considered postural parameters, after the application of suitable under-foot wedge. The present investigation confirm results of a previous study demonstrating the efficacy of under-foot wedge use in leg asymmetry correction, posture re-balancing and spine deformities reduction, pointing out the significant contribution of the 3D opto-electronic measurement approach in the critical process of assessing the correct under-foot wedge size, therapy planning and monitoring. [ABSTRACT FROM AUTHOR]

The rDNA cluster is the genetic locus encoding the ribosomal RNAs and physically defines where ribosomes begin to be assembled. In the yeast Saccharomyces cerevisiae, the highly repetitive structure of this locus makes it a very interesting target for studies about genome stability, chromatin-mediated transcriptional silencing and progression of aging. In fact, recombination among the repeated units is suppressed in a WT cell. Moreover, when genes transcribed by RNA polymerase II are inserted in the rDNA cluster, their transcription is silenced. Finally, the formation of rDNA minicircles (ERCs) has been shown to be one of the causes of aging in yeast. DNA topoisomerase I have been shown to suppress recombination specifically at the rDNA of S.cerevisiae. Moreover, also the chromatin structure of this locus is affected in a top1 strain, because rDNA specific transcriptional silencing is abolished. Nonetheless, the molecular basis of how this enzyme interferes with these functions is yet unknown. Here are reported results obtained by in vivo studies of DNA protein interactions occurring on the rDNA locus. The analyses include a fine mapping of nucleosome positioning; RNA polymerase I transcription factors and DNA topoisomerase I cleavage sites. Important conclusions can be drawn: i) nucleosome positioning in the Non Transcribed Spacer is not affected by RNA polymerase I transcription; ii) the RNA polymerase I transcription factors bind DNA in vivo with a defined hierarchy; iii) the DNA topoisomerase I cleaves the NTS in very specific sites, but cleavage is not induced by RNA polymerase I transcription. These in vivo studies help to characterize the molecular basis of important phenomena as the transcriptional silencing and genome stability in yeast.