Transcription factor TFIIEβ interacts with two exposed positions in helix 2 of the Antennapedia homeodomain to control homeotic function in Drosophila

Abstract Homeoproteins contain the conserved homeodomain (HD) and have an important role determining embryo body plan during development. HDs increase their DNA-binding specificity by interacting with additional cofactors outlining a Hox interactome with a multiplicity of protein-protein interactions. In Drosophila, the first link of functional contact with a general transcription factor (GTF) was found between Antennapedia (Antp) and BIP2 (TFIID complex). Hox proteins also interact with other components of Pol II machinery such as the subunit Med19 from Mediator (MED) complex, TFIIEβand transcription-pausing factor M1BP. All these interactions clearly demonstrate Hox-driven transcriptional regulation, but the precise molecular mechanism remains unclear. In this paper, we focused on the Antp-TFIIEβ protein-protein interface to establish the specific contacts as well as its functional role. Using Bimolecular Fluorescence Complementation (BiFC) in cell culture and in vivo we found that TFIIEβinteracts with Antp through the HD independently of the YPWM motif and the direct physical interaction is at helix 2, specifically aminoacidic positions I32 and H36 of Antp. We also found, through ectopic assays, that these two positions in helix 2 are crucial for Antp homeotic function in head involution, and thoracic and antenna-to tarsus transformations. Interestingly, overexpression of Antp and TFIIEβin the antennal disc showed that this interaction is required for the antenna-to-tarsus transformation. In conclusion, interaction of Antp with TFIIEβis important for the functional specificity of Antennapedia, and amino acids 32 and 36 in Antp HD helix 2 are key for this interaction. Our results open the possibility to more broadly analyze Antp-TFIIEβinteraction on the transcriptional control for the activation and/ or repression of target genes in the Hox interactome during Drosophila development

Interacciones moleculares de la antennapedia con factores generales de la maquinaria de transcripción basal y homeoproteínas en la regulación transcripcional.

Las homeoproteínas presentan estructuras similares y reconocen secuencias de DNA prácticamente idénticas, por lo que una pregunta fundamental en Biología del Desarrollo consiste en determinar el mecanismo funcional que permite esta amplia diversidad funcional. Comparaciones en la secuencia aminoacídica de diferentes homeoproteínas mostraron que además del homeodominio (HD), el tetrapéptido YPWM y regiones polyQ son dominios importantes en la actividad de estas proteínas. El objetivo de la presente tesis es determinar si los factores transcripcionales generales así como las homeoproteínas AbdB y Exd presentan interacción proteína-proteína con los dominios funcionales de Antennapedia (Antp) para la activación y/ó represión de la transcripción durante el desarrollo de D. melanogaster. La estrategia general consistió en determinar las interacciones moleculares de los dominios funcionales de Antp en presencia de los factores transcripcionales TBP, TFIIA, BIP22-89, TFIIB, TFIIE y las homeoproteínas AbdB y Exd144-376 mediante ensayos de transactivación en células Schneider y de Fluorescencia por Complementación Bimolecular (BiFC

Renewable energy research progress in Mexico: A review

Mexico ranks 9th in the world in crude oil reserves, 4th in natural gas reserves in America and it is also highly rich in renewable energy sources (solar, wind, biomasss, hydropower and geothermal). However, the potential of this type of energy has not been fully exploited. Hydropower is the renewable energy source with the highest installed capacity within the country (11,603 MW), while geothermal power capacity (958 MW) makes Mexico to be ranked 4th in the use of this energy worldwide. Wind energy potential is concentrated in five different zones, mainly in the state of Oaxaca, and solar energy has a high potential due to Mexico's ideal location in the so called Solar Belt. Biomass energy has the highest potential (2635 to 3771 PJ/year) and has been the subject of the highest number of research publications in the country during the last 30 years (1982-2012). Universidad Nacional Autonoma de Mexico has led research publications in hydropower, wind, solar and biomass energy and Instituto de Investigaciones Electricas in geothermal energy during this period. According to the General Law for Climate Change the country has set the goal of generating 35% of its energy needs from renewable sources by 2024. This paper presents an overview of the renewable energy options available in Mexico, current status, main positive results to date and future potential. It also analyses barriers hindering improvements and proposes pertinent solutions. © 2014 The Authors