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Abstract Background Antibodies constitute a powerful tool to study protein function, protein localization and protein-protein interactions, as well as for diagnostic and therapeutic purposes. High-throughput antibody development requires faster methodologies with lower antigen consumption. Results Here, we describe a novel methodology to select human monoclonal recombinant antibodies by combining in vitro protein expression, phage display antibody libraries and antibody microarrays. The application of this combination of methodologies permitted us to generate human single-chain variable fragments (scFvs) against two proteins: green fluorescent protein (GFP) and thioredoxin (Trx) in a short time, using as low as 5 μg of purified protein. These scFvs showed specific reactivity against their respective targets and worked well by ELISA and western blot. The scFvs were able to recognise as low as 31 ng of protein of their respective targets by western blot. Conclusion This work describes a novel and miniaturized methodology to obtain human monoclonal recombinant antibodies against any target in a shorter time than other methodologies using only 5 μg of protein. The protocol could be easily adapted to a high-throughput procedure for antibody production. ; RB was supported by a JAE-Doc contract (CSIC). AP is a recipient of a predoctoral FPI grant of the Spanish Ministry of Science and Innovation. This research was supported by grants from the Spanish Ministry of Science and Innovation BIO2009-08818 and Colomics Programme of the regional government of Madrid.We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI). ; Peer Reviewed

14 páginas, 7 figuras, 3 tablas -- PAGS nros. 2382-2395 ; There is a mounting evidence of the existence of autoantibodies associated to cancer progression. Antibodies are the target of choice for serum screening because of their stability and suitability for sensitive immunoassays. By using commercial protein microarrays containing 8000 human proteins, we examined 20 sera from colorectal cancer (CRC) patients and healthy subjects to identify autoantibody patterns and associated antigens. Forty-three proteins were differentially recognized by tumoral and reference sera (p value <0.04) in the protein microarrays. Five immunoreactive antigens, PIM1, MAPKAPK3, STK4, SRC, and FGFR4, showed the highest prevalence in cancer samples, whereas ACVR2B was more abundant in normal sera. Three of them, PIM1, MAPKAPK3, and ACVR2B, were used for further validation. A significant increase in the expression level of these antigens on CRC cell lines and colonic mucosa was confirmed by immunoblotting and immunohistochemistry on tissue microarrays. A diagnostic ELISA based on the combination of MAPKAPK3 and ACVR2B proteins yielded specificity and sensitivity values of 73.9 and 83.3% (area under the curve, 0.85), respectively, for CRC discrimination after using an independent sample set containing 94 sera representative of different stages of progression and control subjects. In summary, these studies confirmed the presence of specific autoantibodies for CRC and revealed new individual markers of disease (PIM1, MAPKAPK3, and ACVR2B) with the potential to diagnose CRC with higher specificity and sensitivity than previously reported serum biomarkers ; This work was supported in part by Spanish Ministry of Education and Science Grant BIO2006-07689 and grants from the Colomics program of the regional government of Madrid and from the Fundación Médica Mutua Madrileña ; Peer reviewed

11 páginas, 7 figuras -- PAGS nros. 2812-2822 ; Genomic DNA is packed in chromatin fibers organized in higher-order structures within the interphase nucleus. One level of organization involves the formation of chromatin loops that may provide a favorable environment to processes such as DNA replication, transcription, and repair. However, little is known about the mechanistic basis of this structuration. Here we demonstrate that cohesin participates in the spatial organization of DNA replication factories in human cells. Cohesin is enriched at replication origins and interacts with prereplication complex proteins. Down-regulation of cohesin slows down S-phase progression by limiting the number of active origins and increasing the length of chromatin loops that correspond with replicon units. These results give a new dimension to the role of cohesin in the architectural organization of interphase chromatin, by showing its participation in DNA replication ; This work was supported by the Spanish Ministry of Science and Innovation (J.M., A.L., and I.C.), Consolider Ingenio 2010 and Fundación Caja Madrid (J.M. and A.L.), Comunidad de Madrid (I.C.), and Institut National du Cancer and Association pour la Recherche sur le Cancer (E.S.). E.G. and V.C. were supported by the Fondation pour la Recherche Médicale and Institut National du Cancer, respectively. A.I. was supported by a fellowship from the Basque Government ; Peer reviewed