This thesis focuses on the role of RAD 18 in DNA double-strand break (DSB ) repair.
Much is known about the role of RAD 18, and its critical substrate PCNA in replication
damage bypass (RDB ) repair. However, the roles of RAD 18 in DSB repair are still
elusive, although several interaction partners of RAD 18 have been identified, and the
radiation-sensitivity of Rad18 knockout cells has shown that this E3 ligase is active in
DSB repair.
First, a general introduction on the possible involvement of RAD 18 in DSB repair
mechanisms and RDB that operate in mitotic and meiotic cells is presented in Chapter
1. In Chapter 2, we examined the dynamic localization of human RAD 18 during the
cell cycle and after DNA damage in living cells. The DNA damage response functions
of RAD 18 after different types of damages (UV and IR) were analyzed. In order to
distinguish DSB repair functions of RAD 18 from functions in the RDB pathway, the
dynamics of the known substrate of RAD 18 in RDB , PCNA , was also examined in
living cells. Subsequently, we performed a structure-function analysis of RAD 18 and
examined the requirements for RAD 18 localization to DSB s in mitotic cells. We also
show that RAD 18 facilitates recruitment of the checkpoint protein RAD 9 to DSB repair
sites (Chapter 3). Next, we examined the role of mouse RAD 18 in meiotic DSB repair
by analysing the testicular phenotype of Rad18 knockdown mice (Chapter 4). Also, the
function of PCNA modification in meiosis was examined in Chapter 5. We propose
a possible role of SU MOylated PCNA in meiotic crossover control. Based upon our
observations on RAD 18 localization to DSB s in meiosis, we have performed a detailed
analysis of the accumulation of DSB -repair proteins in the presence and absence of
meiotic (SPO 11-induced) DSB s in spermatocytes, in relation to chromosome pairing
(Chapter 6). Finally, we present a general discussion of the results described in Chapter
2 - 6 and present a model of RAD 18 functions in DSB repair (Chapter 7).
No comments:
Post a Comment