Caracterización de proteínas asociadas al nucleoide ('Nucleoid-Associated Proteins' [NAPs]) en Bacillus subtilis

Autor: Cubillo Thiebaut, Cristina
Přispěvatelé: Rodríguez Romero, Julio L., Alonso Navarro, Juan Carlos
Jazyk: Spanish; Castilian
Rok vydání: 2021
Předmět:
Zdroj: Archivo Digital UPM
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Popis: Natural transformation is one of the main mechanisms for horizontal gene transfer (HGT) that takes place in bacteria. This allows them to acquire new genetic information, contributing to the spread of antibiotic resistance, metabolic pathways, as well as the emergence of new pathogens. Hence, it is essential to gain basic knowledge of these mechanisms to combat the antibiotic resistance one of the greatest human health challenges. Furthermore, bacteria are constantly subjected to different types of DNA damage, that arise as a consequence of both internal and external factors. Since maintaining the integrity of the genome is essential for cell survival, bacteria cells have developed several mechanisms to prevent, tolerate and repair the damage. LrpC, Hbsu and Rok are Nucleoid Associated Proteins (NAPs) of Bacillus subtilis that bind DNA, facilitating its compaction and structure. Our aim in this work is to see how these proteins are involved in natural transformation and DNA repair mechanisms. What it is shown, is that inactivation of these proteins increases the efficiency of intraspecies chromosomal transformation, and to a lesser extent the efficiency of plasmid transformation. This suggests that these proteins have mainly a structural function. They are naturally associated with DNA, hindering the transformation process. On the other hand, it was found that when B. subtilis cells were exposed to different DNA damage-inducing agents (MMS, 4NQO and MMC), cell survival for Hbsu inactivation mutants (hbsu4755) was decreased compared to the wt. Therefore, it has been shown that Hbsu contributes to the repair or reactivation of the replication fork, that stops in the face of induced damage, favoring cell survival. However, it was also seen that it does not contribute to the repair of fork collapse (damage induced by MMC), despite reactivating the fork when stalled by damage introduced by MMC or 4NQO. Finally, a search for other possible NAPs was carried out, with the aim of subjecting them to the same assays and analyzing their role in the aforementioned mechanisms. The construction of the ebfC:ery knockout mutant was attempted.
Databáze: OpenAIRE
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