DNA damage responses involved in the recovery of replication and transcription blockage in human cells.

Author(s)

Leonardo Carmo de Andrade Lima

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2014-07-14

Examining board members

Carlos Frederico Martins Menck; Fábio Luís Forti; Pedro Alexandre Favoretto Galante; Joao Gustavo Pessini Amarante Mendes; Enrique Mario Boccardo Pierulivo

• Advisor: Carlos Frederico Martins Menck

Abstract

Ultraviolet (UV) light stalls replication and transcription due to the formation of lesions that distort DNA. We found that ATR silencing promotes early induction of apoptosis after UVB light in human fibroblasts immortalized with SV40 and even cells proficient in DNA repair and translesion synthesis were unable to reach mitosis after ATR depletion. This kinase is also a promising target for sensitizing tumors with p53 mutations to chemotherapeutic that block replication, such as cisplatin, and the oxidative stress inducer chloroquine. In addition to blocking the replication, DNA damage arrest the synthesis of RNA. We used next-generation sequencing to map and analyze the nascent RNA transcription recovery genome-wide. We confirmed that longer genes are more inhibited following UV light, however, the level of gene expression does not contribute to the recovery of transcription. Moreover, DNA repair is similar among genes with different recovery of transcription and further regulation, besides DNA damage removal, must exist to promote resumption of RNA synthesis. (AU)