Phasing in heterochromatin during development
| Autor: | Robert J. Duronio, Robin L. Armstrong |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
animal structures
Time Factors Heterochromatin Cellular differentiation Embryonic Development Biology Genome 03 medical and health sciences 0302 clinical medicine Genetics Constitutive heterochromatin Animals Drosophila Proteins Gene 030304 developmental biology 0303 health sciences Zygote fungi Cell Cycle Drosophila embryogenesis Gene Expression Regulation Developmental Embryo Histone-Lysine N-Methyltransferase Cell biology Drosophila melanogaster 030220 oncology & carcinogenesis embryonic structures Perspective Drosophila Developmental Biology Research Paper |
| Popis: | Acquisition of chromatin modifications during embryogenesis distinguishes different regions of an initially naïve genome. In many organisms, repetitive DNA is packaged into constitutive heterochromatin that is marked by di/trimethylation of histone H3K9 and the associated protein HP1a. These modifications enforce the unique epigenetic properties of heterochromatin. However, in the early Drosophila melanogaster embryo, the heterochromatin lacks these modifications, which appear only later, when rapid embryonic cell cycles slow down at the midblastula transition (MBT). Here we focus on the initial steps restoring heterochromatic modifications in the embryo. We describe the JabbaTrap, a technique for inactivating maternally provided proteins in embryos. Using the JabbaTrap, we reveal a major requirement for the methyltransferase Eggless/SetDB1 in the establishment of heterochromatin. In contrast, other methyltransferases contribute minimally. Live imaging reveals that endogenous Eggless gradually accumulates on chromatin in interphase but then dissociates in mitosis, and its accumulation must restart in the next cell cycle. Cell cycle slowing as the embryo approaches the MBT permits increasing accumulation and action of Eggless at its targets. Experimental manipulation of interphase duration shows that cell cycle speed regulates Eggless. We propose that developmental slowing of the cell cycle times embryonic heterochromatin formation. |
| Databáze: | OpenAIRE |
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