The chromodomain-containing NH(2)-terminus of Chromator interacts with histone H1 and is required for correct targeting to chromatin.
The chromodomain protein, Chromator, can be divided into two main domains, a NH(2)-terminal domain (NTD) containing the chromodomain (ChD) and a COOH-terminal domain (CTD) containing a nuclear localization signal. During interphase Chromator is localized to chromosomes; however, during cell division Chromator redistributes to form a macro molecular spindle matrix complex together with other nuclear proteins that contribute to microtubule spindle dynamics and proper chromosome segregation during mitosis. It has previously been demonstrated that the CTD is sufficient for targeting Chromator to the spindle matrix. In this study, we show that the NTD domain of Chromator is required for proper localization to chromatin during interphase and that chromosome morphology defects observed in Chromator hypomorphic mutant backgrounds can be largely rescued by expression of this domain. Furthermore, we show that the ChD domain can interact with histone H1 and that this interaction is necessary for correct chromatin targeting. Nonetheless, that localization to chromatin still occurs in the absence of the ChD indicates that Chromator possesses a second mechanism for chromatin association and we provide evidence that this association is mediated by other sequences residing in the NTD. Taken together these findings suggest that Chromator's chromatin functions are largely governed by the NH(2)-terminal domain whereas functions related to mitosis are mediated mainly by COOH-terminal sequences.
Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
Changfu
C
Yao
Yun
Y
Ding
Weili
W
Cai
Chao
C
Wang
Jack
J
Girton
Kristen M
KM
Johansen
Jørgen
J
Johansen
D000818:Animals; D002843:Chromatin / Q000737:chemistry* / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005822:Genetic Vectors / Q000235:genetics; D006657:Histones / Q000378:metabolism*; D015151:Immunoblotting; D047468:Immunoprecipitation; D007399:Interphase / Q000502:physiology*; D008958:Models, Molecular; D034521:Nuclear Matrix-Associated Proteins / Q000378:metabolism*; D017434:Protein Structure, Tertiary
C498868:Chro protein, Drosophila; D002843:Chromatin; D029721:Drosophila Proteins; D006657:Histones; D034521:Nuclear Matrix-Associated Proteins