LIFE SCIENCES, 16

Author: Portela Mestres Anna.
Year: 2006.
University: AUTÓNOMA DE BARCELONA.
Place of defense: Facultat de Biociències.
Place of preparation: Universitat Autònoma de Barcelona.

Summary: This thesis work focuses on the study of various mutants zeste1 and the effect that this change has on the regulation of transcription in a variety of genes. First explored the male strains M115 and RM115 whose main feature, besides being carriers of the mutation z1, is the insertion of an item transponible FB-NOF in the third intrón of CG32795, which form with a pair of w gene head-to-tail. To explore what is the effect of the insertion of FB-NOF in an environment z1, it was necessary to first characterize the gene CG32795 at the level of mRNA sequence and prediction of the potential role of the protein encoded. We found several variants of splicing, both for its extreme 5 'to the 3', similar but different variants predicted earlier. Knowing more in depth this gene, we set out to study the possible effects of the insertion of FB-NOF respect to the expression of genes w CG32795. The results led us to a more detailed study of the expression of w in different parts of the body, taking into account the specificity of tissue that interaction zeste-white presents. Thus, we saw that the gene w is not affected by the insertion of FB-NOF in its extreme 3 'and that differences in expression observed are due to the doubling of Zeste Binding Site of w in an environment z1. However, the insertion of FB-NOF in the third intrón of CG32795 it modifies the expression of this gene. Not only the insertion is responsible for altering the expression of CG32795 but the rearrangement that occurs in strain RM115 eliminating w copy of the original and leaving it doubled in M115. The second part of this thesis is the study of female mutants z1. We analyzed the expression of two genes with a ZBS (w dpp) and watched as it reduces the expression of these genes in females z1. In addition, studying the expression of the gene CG32795 note that the effect of the interaction zeste-white is local, without affecting this gene while his extreme 5 'is just 700bp end 3' gene w. The reduction of the expression made us think that it could be due to changes in the structure of chromatin, since aggregates Zeste in ZBS are responsible for the recruitment of chromatin remodeler complex BRM, thus facilitating the transcript. A test nucleasa micrococal detect some changes in the positioning of nucleosomas in ZBS of w dpp, with the positioning females z1 stricter. If the complex BRM is responsible for these differences, we think that methylation patterns could also be altered, since many factors associated with the complex SWI / SNF have been linked to efforts by regulating the expression modification. By testing DNA modification by sodium bisulphite studied methylation patterns of five regions. Surprisingly, the ZBS of wy of dpp, and the regions close to them, were hipometilados in females z1. Ignorance about the overall methylation in D. Melanogaster made us raise which may be the target sequences of methylation in this species. So we conducted a statistical study on the two bases which are pre - and post-Cs metiladas in our streams. We extracted differences in the frequencies of each position and established himself as a sequence to be more frequent metilada ApDp5mCpDpD. Still, it's a very degenerate sequence, and more studies are needed to confirm deep and broad.

Author: Cardús Figueras Anna.
Year: 2006.
University: LLEIDA.
Place of defense: Universitat de Lleida. Departament de Medicina.
Place of preparation: Universitat de Lleida.

Summary: The atherosclerosis is a process characterized by thickening and hardening of the walls of the arteries. This process is accelerated in patients with chronic renal failure (CRF). In addition, these patients suffer a decline in the synthesis of 1,25-dihidroxivitamina D3 (1,25 (OH) 2D3), which leads them to other complications such as secondary hyperparathyroidism (HPT2). For this reason it is often used 1.25 (OH) 2D3 in the treatment of HPT2. The effect of 1,25 (OH) 2D3 on the calcification of the smooth muscle cells (CMLV) is fairly evaluated, but their impact on non-proliferation is very clear. We analyze the effect of 1,25 (OH) 2D3 on the proliferation of CMLV by incorporation of BrdU and flow cytometry. Our results show that 1,25 (OH) 2D3 induces the proliferation of CMLV a dose dependent manner in both quiescent as a proliferative state. The effect of 1,25 (OH) 2D3 on the proliferation correlated with increased expression of the growth factor vascular endothelial (vascular endothelial growth factor, VEGF). In addition, by inhibiting the activity of this VEGF note that the proliferation induced by 1,25 (OH) 2D3 is completely blocked. From these results we analyze the promoter region of VEGF and note the presence of 3 areas with sequences very similar to the response elements of vitamin D (VDRE) present in the target genes of 1.25 (OH) 2D3. From the analysis by Chromatin Immunoprecipitation (ChIP) encounter an VDRE in the promoter of VEGF where the vitamin D receptor (VDR) joins after treatment with 1,25 (OH) 2D3. Then we raised a different model to compare the effect of 1,25 (OH) 2D3 and 19-nor-1, 25 (OH) 2D2 in the process of proliferation and calcification in vitro, ex vivo and in vivo in a model rat IRC. We note an increase in proliferation in the CMLV, rings artery and aorta in animals treated with 1,25 (OH) 2D3, but not in treatments 19-nor-1, 25 (OH) 2D2.

Author: BARRIUSO IGLESIAS MÓNICA.
Year: 2006.
University: LEÓN.
Place of defense: FACULTA DE CIENCIAS BIOLÓGICAS Y AMBIENTALES.
Place of preparation: FACULTAD DE CIENCIAS BIOLÓGICAS Y AMBIENTALES.

Summary: This report contains the results of the study on the response to stress by pH in C. Glutamicum, thus allowing a wider knowledge of promoters regulated by a change in pH. The importance of this work lies in the great interest in the study of promoters adjustable, and that can be used to express biotechnologically at will (in this case, depending on the pH of the crop) genes that are connected to these promoters. It describes for the first time Corynebacterium glutamicum ATCC 13032 as a microorganism alcalófilo, supported by a phenomenon of adaptation to pH observed when using crops at pH 9.0 as crop seeds to start at pH 10.0. The proteome citoplasmático and membrane C.glutamicum WT different concidiciones pH appreciated how 21 proteins showed variation in their expression. It has been observed that there is a possible mechanism for regulating pH core who would be involved in the respiratory chain and the cycle of acid tricarboxílicos. Among the proteins identified was elected the operon of F0F1-ATP synthase membrane, as a candidate to study induction of promoter before changes in pH. The study of the expression of operon atpBEFHAGDC or operon f0f1 (F0F1-ATP synthase), there is a transcribed from 7'5 kb and a transcribed monocistrónico of 1.2 kb, with both induced a pH 9.0. It has characterized the promoter region of operon f0f1 identifying a site of initiation of transcription (TSP), whose consensus sequences for the boxes -10 and -35 suggest regulation by the factor sH. By Northern with the strain C. Glutamicum? SigH (strain delecionada in the gene sigH, which encodes a factor sH), it was concluded that when this gene is deleciona are obtained again transcribed 7'5 and 1.2 kb but induction at pH 9.0 of operon observed earlier in both transcribed, disappears in the mutant. The gene sigH of C. Glutamicum form an operon along with the gene cg0877, speaking in a transcribed bicistrónico of 0'9 kb induced pH 9.0, and to a lesser extent at pH 6.0. Through tests EMSA, it has been determined that the protein SigmaH joins the promoter of operon f0f1, linking directly to this factor sigma with a basic pH regulation in the operon. By RT-PCR have demonstrated the existence of gene atpI located upstream of operon f0f1, regardless of how they are transcribed operon and that its expression is also induced at pH 9.0. The characterization of the promoter region of this gene has identified a TSP, which unlike the promoter of operon f0f1, appears to be controlled by a factor sigma vegetative. The deletion of the gene atpI in C. Glutamicum confirms the non-essential nature of the same. Unable to establish a specific role for the protein AtpI, although analysis of all the results for the same (growth kinetics, testing ATPase activity, the effect of Mg2 + in its growth, and proteome citoplasmático and membrane) , suggests a character modulator focused on the metabolism Central (glicólisis and cycle acids tricarboxílicos), the metabolism of sulphurous compounds and nitrogen metabolism.