During early embryogenesis cells become determined to differentiate along specialized pathways. The molecular events underlying these processes are not understood. The long-term objective of this project is to obtain an understanding of the steps involved in nuclear determination and differentiation. To this end, specific attention is being paid to changes in histone composition, histone modifications and chromatin structure in specific nuclei undergoing divergent pathways of differentiation. Conjugation in Tetrahymena will be used as a model to study nuclear determination and differentiation during development. In this system, nuclei derived from daughter products of a single mitotic division differentiate into distinctly different products, macro-and micronuclei depending upon their location within the cell. In many ways these events are directly analogous to cellular determination and differentiation which characterize embryogenesis of higher animals. A variety of biochemical, cytological, immunological and micromanipulation approaches will be used to 1) further define the histone composition, histone modification and chromatin structure in synchronous populations of developing nuclei isolated from conjugating cells as well as nuclei in various stages of the cell cycle; 2) fractionate, purify and characterize enzymes which play a role in the histone remodeling process; 3) purify, characterize and compare the linker histones in micro- and macronuclei and study their effects on chromatin higher order structures; 4) generate and use antibodies to specific histones as probes in projects which include protein purification, protein structure-function relationships, chromatin structure and fractionation, cloning of Tetrahymena histone genes as well as immunofluorescent analyses with conjugating cells; and 5) microinject molecules into and micromanipulate nuclei within living cells to ask questions concerning the targeting of histones to the proper nuclear compartment, the consequences on histone metabolism and function by perturbation with specific antibody molecules and the role that cytoplasm plays in directing nuclear determination and differentiation. Understanding these mechanisms in normal development is essential if we are to understand cases of abnormal development, some congenital diseases and certain pathological situations such as neoplastic transformation.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
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Molecular Cytology Study Section (CTY)
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University of Virginia
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Ruthenburg, Alexander J; Li, Haitao; Milne, Thomas A et al. (2011) Recognition of a mononucleosomal histone modification pattern by BPTF via multivalent interactions. Cell 145:692-706
Duncan, Elizabeth M; Allis, C David (2011) Errors in erasure: links between histone lysine methylation removal and disease. Prog Drug Res 67:69-90
Chi, Ping; Allis, C David; Wang, Gang Greg (2010) Covalent histone modifications--miswritten, misinterpreted and mis-erased in human cancers. Nat Rev Cancer 10:457-69
Lewis, Peter W; Elsaesser, Simon J; Noh, Kyung-Min et al. (2010) Daxx is an H3.3-specific histone chaperone and cooperates with ATRX in replication-independent chromatin assembly at telomeres. Proc Natl Acad Sci U S A 107:14075-80
Goldberg, Aaron D; Banaszynski, Laura A; Noh, Kyung-Min et al. (2010) Distinct factors control histone variant H3.3 localization at specific genomic regions. Cell 140:678-91
Guan, Zeqiang; Hughes, Christina M; Kosiyatrakul, Settapong et al. (2009) Decreased replication origin activity in temporal transition regions. J Cell Biol 187:623-35
Nicklay, Joshua J; Shechter, David; Chitta, Raghu K et al. (2009) Analysis of histones in Xenopus laevis. II. mass spectrometry reveals an index of cell type-specific modifications on H3 and H4. J Biol Chem 284:1075-85
Shechter, David; Nicklay, Joshua J; Chitta, Raghu K et al. (2009) Analysis of histones in Xenopus laevis. I. A distinct index of enriched variants and modifications exists in each cell type and is remodeled during developmental transitions. J Biol Chem 284:1064-74
Duncan, Elizabeth M; Muratore-Schroeder, Tara L; Cook, Richard G et al. (2008) Cathepsin L proteolytically processes histone H3 during mouse embryonic stem cell differentiation. Cell 135:284-94
Fischle, Wolfgang; Franz, Henriette; Jacobs, Steven A et al. (2008) Specificity of the chromodomain Y chromosome family of chromodomains for lysine-methylated ARK(S/T) motifs. J Biol Chem 283:19626-35

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