Examinando por Autor "Veloso, Felipe A."

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    AlterORF: A database of alternate open reading frames
    (Oxford University Press, 2008-01) Pedroso, Inti; Rivera, Gustavo; Lazo, Felipe; Chacón, Max; Ossandón, Francisco; Veloso, Felipe A.; Holmes, David S.
    AlterORF is a searchable database that contains information regarding alternate open reading frames (ORFs) for over 1.5 million genes in 481 prokaryotic genomes. The objective of the database is to provide a platform for improving genome annotation and to serve as an aid for the identification of prokaryotic genes that potentially encode proteins in more than one reading frame. The AlterORF Database can be accessed through a web interface at www.alterorf.cl. © 2007 The Author(s).
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    Bioinformatic prediction and experimental verification of Fur-regulated genes in the extreme acidophile Acidithiobacillus ferrooxidans
    (2007-04) Quatrini, Raquel; Lefimil, Claudia; Veloso, Felipe A.; Pedroso, Inti; Holmes, David S.; Jedlicki, Eugenia
    The γ-proteobacterium Acidithiobacillus ferrooxidans lives in extremely acidic conditions (pH 2) and, unlike most organisms, is confronted with an abundant supply of soluble iron. It is also unusual in that it oxidizes iron as an energy source. Consequently, it faces the challenging dual problems of (i) maintaining intracellular iron homeostasis when confronted with extremely high environmental loads of iron and (ii) of regulating the use of iron both as an energy source and as a metabolic micronutrient. A combined bioinformatic and experimental approach was undertaken to identify Fur regulatory sites in the genome of A. ferrooxidans and to gain insight into the constitution of its Fur regulon. Fur regulatory targets associated with a variety of cellular functions including metal trafficking (e.g. feoPABC, tdr, tonBexbBD, copB, cdf), utilization (e.g. fdx, nif, transcriptional regulation (e.g. phoB, irr, iscR) and redox balance (grx), trx, gst) were identified. Selected predicted Fur regulatory sites were confirmed by FURTA, EMSA and in vitro transcription analyses. This study provides the first model for a Fur-binding site consensus sequence in an acidophilic iron-oxidizing microorganism and lays the foundation for future studies aimed at deepening our understanding of the regulatory networks that control iron uptake, homeostasis and oxidation in extreme acidophiles. © 2007 The Author(s).
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    The specification of cortical subcerebral projection neurons depends on the direct repression of TBR1 by CTIP1/BCL11a
    (Society for Neuroscience, 2015-05) Cánovas, José; Berndt, F. Andrés; Sepúlveda, Hugo; Aguilar, Rodrigo; Veloso, Felipe A.; Montecino, Martín; Oliva, Carlos; Maass, Juan C.; Sierralta, Jimena; Kukuljan, Manuel
    The acquisition of distinct neuronal fates is fundamental for the function of the cerebral cortex. We find that the development of subcerebral projections from layer 5 neurons in the mouse neocortex depends on the high levels of expression of the transcription factor CTIP1; CTIP1 is coexpressed with CTIP2 in neurons that project to subcerebral targets and with SATB2 in those that project to the contralateral cortex. CTIP1 directly represses Tbr1 in layer 5, which appears as a critical step for the acquisition of the subcerebral fate. In contrast, lower levels of CTIP1 in layer 6 are required for TBR1 expression, which directs the corticothalamic fate. CTIP1 does not appear to play a critical role in the acquisition of the callosal projection fate in layer 5. These findings unravel a key step in the acquisition of cell fate for closely related corticofugal neurons and indicate that differential dosages of transcriptions factors are critical to specify different neuronal identities. © 2015 the authors.