The COOH-terminal Domain of the JIL-1 Histone H3S10 Kinase Interacts with Histone H3 and Is Required for Correct Targeting to Chromatin
The JIL-1 histone H3S10 kinase in Drosophila localizes specifically to euchromatic interband regions of polytene chromosomes and is enriched 2-fold on the male X chromosome. JIL-1 can be divided into four main domains including an NH2-terminal domain, two separate kinase domains, and a COOH-terminal domain. Our results demonstrate that the COOH-terminal domain of JIL-1 is necessary and sufficient for correct chromosome targeting to autosomes but that both COOH- and NH2-terminal sequences are necessary for enrichment on the male X chromosome. We furthermore show that a small 53-amino acid region within the COOH-terminal domain can interact with the tail region of histone H3, suggesting that this interaction is necessary for the correct chromatin targeting of the JIL-1 kinase. Interestingly, our data indicate that the COOH-terminal domain alone is sufficient to rescue JIL-1 null mutant polytene chromosome defects including those of the male X chromosome. Nonetheless, we also found that a truncated JIL-1 protein which was without the COOH-terminal domain but retained histone H3S10 kinase activity was able to rescue autosome as well as partially rescue male X polytene chromosome morphology. Taken together these findings indicate that JIL-1 may participate in regulating chromatin structure by multiple and partially redundant mechanisms.
This research was originally published in the Journal of Biological Chemistry. Bao, Xiaomin, Weili Cai, Huai Deng, Weiguo Zhang, Robert Krencik, Jack Girton, Jørgen Johansen, and Kristen M. Johansen. "The COOH-terminal domain of the JIL-1 histone H3S10 kinase interacts with histone H3 and is required for correct targeting to chromatin." Journal of Biological Chemistry 283, no. 47 (2008): 32741-32750. © the American Society for Biochemistry and Molecular Biology. doi: 10.1074/jbc.M806227200.