UNIVERSITY OF MASSACHUSETTS
The mitotic repsonse to DNA damage. DNA damage disrupts mitotic chromosome segregation through a poorly defined process termed mitotic catastrophe. During early Drosophila embryogensis, this processi is linked to Chk2 kinase dependent centrosome inactivation and dissociation of the ?-Tubulin ring complex (?TuRC) from a core centrosome scaffold (Sibon et al., 2000; Takada et al., 2007). 2-D gel and Western blotting studies reveal 5 ?-Tubulin isoforms in control embryos. DNA damage triggers a Chk2-dependent shift to 2 isoforms. Phosphatase treatmentleads to a similar shift, suggesting that Chk2 activation leads to ?-Tubulin dephosphporylation. Funds requested under this supplement will be used to complete the biochemical and functional analysis of damage induced ?Tubulin modifications.