| Popis: |
Trinucleotide repeats (TNRs) are sequences prone to formation of non-B DNAstructures and mutations; undergo expansions in vivo to cause various inheritedneurodegenerative diseases. Hairpin structures formed during DNA replication orrepair can cause replication fork stalling and if left unrepaired could cause single ordouble strand DNA breaks. To test and study this hypothesis we have devised a noveltwo color marker gene assay to detect DNA breaks at TNRs. By inducing replicationstress our results show that TNRs are prone to DNA strand breaks and it is dependenton the repeat tract length. Double strand breaks at structured DNA are repaireddifferently than `clean’ DSBs. The cells which undergo breaks die off, possibly due toinability to repair breaks. Translesion polymerases help tolerate DNA damage at TNRregion. |
