Low-complexity regions in proteins as a source of evolutionary innovation
In this thesis we aimed to study evolutionary implications of low-complexity regions, protein sequences of very simple amino acid composition. Its uncontrolled expansion causes several human diseases, including Huntington’s disease and other neurodegenerative and developmental diseases. However, the...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2013 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/113603 |
| Acceso en línea: | http://hdl.handle.net/10803/113603 |
| Access Level: | acceso abierto |
| Palabra clave: | Low-complexity regions Amino acid tandem repeats Simple sequence Gene age Protein domain evolution Transcription factor Paralogous protein Repeticions en tandem d’aminoàcids Seqüències simples Edat dels gens Evolució de dominis de proteïnes Factor de transcripció Proteïnes paràlogues Regions de baixa complexitat 575 616.8 |
| Sumario: | In this thesis we aimed to study evolutionary implications of low-complexity regions, protein sequences of very simple amino acid composition. Its uncontrolled expansion causes several human diseases, including Huntington’s disease and other neurodegenerative and developmental diseases. However, they are surprisingly abundant in proteins, which seem paradoxical given their high pathogenic potential. Moreover, experimental data has shown that the formation of novel LCRs, or the modification of existing ones, can have functional consequences. First we wanted to perform a descriptive analysis of low-complexity regions in chordates focusing on lineage and age related features of LCR evolution. Second, we want to assess why low-complexity regions are so common in eukaryotic proteins. Two hypotheses have been proposed: on one hand, they may be an important source of genetic variability and might be involved in adaptive processes. To investigate whether LCRs are important players in the acquisition of novel functions, we examined transcription factor gene duplicates. On the other hand, low-complexity regions may also contribute to the formation of novel coding sequences, facilitating the generation of novel protein functions. We have tested this hypothesis by examining the content of low-complexity sequences in proteins of different age. Both analysis let us to conclude that low-complexity regions may be involved in protein diversification, either providing new functional sequences that will modify existing proteins or being involved in the formation of novel protein coding sequences. |
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