Chromatin regulates origin activity in Drosophila follicle cells

Aggarwal, Bhagwan D.; Calvi, Brian R.

doi:10.1038/nature02694

Cited by 244 publications

(256 citation statements)

References 29 publications

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“…Also E2f1 alters chromatin structure interacting with the tumor-suppressor and cell cycle regulator Rb, which recruits histone deacetylase complexes. In agreement with these results, nucleosomes are hyperacetylated at ACE3 and ori-␤ sequences (Aggarwal and Calvi, 2004). More information on the dynamics of DNA replication at the chorion loci came from a study of Claycomb et al (2002).…”

Section: Chorion Gene Amplificationsupporting

confidence: 71%

Building up the Drosophila eggshell: First of all the eggshell genes must be transcribed

Cavaliere

Bernardi

Romani

et al. 2008

Developmental Dynamics

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The Drosophila eggshell provides a model system for studying the assembly of extracellular matrix. Eggshell formation is a complex process that requires time-coordinated synthesis, cleavage, and transport of various proteins and finally cross-linking mediated by particular functional domains. It has been suggested that the eggshell can act as a storage site for spatial cues involved in embryonic pattern formation. Its structural components are synthesized in the somatic follicle cells in a precise temporally and spatially regulated manner. This review will summarize our knowledge of eggshell gene expression. We will discuss the amplification of the chorion gene clusters and the data acquired on the expression patterns and the regulatory elements controlling transcription of eggshell genes. We will then focus on the findings that correlate follicular epithelium patterning and eggshell gene expression, and discuss the interesting perspectives of an involvement in eggshell assembly of embryonic patterning cues. Developmental Dynamics 237:2061-2072, 2008.

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Section: Chorion Gene Amplificationsupporting

confidence: 71%

Building up the Drosophila eggshell: First of all the eggshell genes must be transcribed

Cavaliere

Bernardi

Romani

et al. 2008

Developmental Dynamics

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“…In human cells, histone acetylation has been correlated with replication timing (Cimbora et al, 2000), and HBO1 HAT (Iizuka and Stillman, 1999), associates with components of the replication machinery (Burke et al, 2001). This was confirmed by a study showing that histones are hyperacetylated at the active origins of replication and that this coincides with binding of the origin recognition complex (Aggarwal and Calvi, 2004). However, the mechanism by which histone acetylation affects the time of firing is not understood.…”

Section: Replicationmentioning

confidence: 91%

Orchestration of chromatin-based processes: mind the TRRAP

et al. 2007

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Chromatin modifications at core histones including acetylation, methylation, phosphorylation and ubiquitination play an important role in diverse biological processes. Acetylation of specific lysine residues within the N terminus tails of core histones is arguably the most studied histone modification; however, its precise roles in different cellular processes and how it is disrupted in human diseases remain poorly understood. In the last decade, a number of histone acetyltransferases (HATs) enzymes responsible for histone acetylation, has been identified and functional studies have begun to unravel their biological functions. The activity of many HATs is dependent on HAT complexes, the multiprotein assemblies that contain one HAT catalytic subunit, adapter proteins, several other molecules of unknown function and a large protein called TRansformation/tRanscription domain-Associated Protein (TRRAP). As a common component of many HAT complexes, TRRAP appears to be responsible for the recruitment of these complexes to chromatin during transcription, replication and DNA repair. Recent studies have shed new light on the role of TRRAP in HAT complexes as well as mechanisms by which it mediates diverse cellular processes. Thus, TRRAP appears to be responsible for a concerted and context-dependent recruitment of HATs and coordination of distinct chromatin-based processes, suggesting that its deregulation may contribute to diseases. In this review, we summarize recent developments in our understanding of the function of TRRAP and TRRAP-containing HAT complexes in normal cellular processes and speculate on the mechanism underlying abnormal events that may lead to human diseases such as cancer.

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“…In D. melanogaster follicle cells, an interaction of ORC with E2F transcription factors 64,65 -possibly in conjunction with a developmentally regulated Myb-oncoprotein-containing complex 66 and the histone de-acetylase Rpd3 (REF. 67) -seems to orchestrate a developmentally regulated redistribution of ORC to facilitate amplification of the chorion gene cluster. Chromosomal activities such as transcription can also destabilize nucleosomes and create superhelical tension, which might explain the transcription-dependent origin activity that has been described in several systems 68-70 .…”

Section: Box 3 | Regulation Downstream Of the Initiator-replicator Inmentioning

confidence: 99%

In search of the holy replicator

Gilbert

2004

Nat Rev Mol Cell Biol

126

132

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After 40 years of searching for the eukaryotic replicator sequence, it is time to abandon the concept of 'the' replicator as a single genetic entity. Here I propose a 'relaxed replicon model' in which a positive initiator-replicator interaction is facilitated by a combination of several complex features of chromatin. An important question for the future is whether the positions of replication origins are simply a passive result of local chromatin structure or are actively localized to coordinate replication with other chromosomal activities.In the summer of 1962, François Jacob and Sydney Brenner sketched in the sand of France's La Tranche-sur-Mer a model (FIG. 1a) to explain the regulation of DNA synthesis in bacteria 1 . Their 'replicon model' proposed that replication was regulated by a positive interaction between an initiator protein, which is encoded by a structural gene, and a specific genetic element of recognition, which is known as the replicator. Although originally intended to explain the replication of circular bacterial chromosomes, the replicon model was quickly adopted as the paradigm for eukaryotic chromosomes as well (FIG. 1b). Proteins with the properties of initiators have been identified in species from Escherichia coli to man. By contrast, genetically defined replicators have yet to be identified in most eukaryotes and are clearly dispensable for replication in many eukaryotic systems. Even in its shortcomings, though, the model has been useful. Indeed, the replicon model was the driving force behind the discovery of bacterial and budding yeast replicators as well as initiator proteins -from dnaA in prokaryotes 2 to the origin-recognition complex (ORC) in eukaryotes 3 . Indeed, all cellular chromosomes can be thought of as replicons, or clusters of replicons -the replication of which is regulated, at least in part, by a positive initiator-replicator interaction.In this historical perspective, I will summarize the salient findings over the course of these four decades (TIMELINE), with a focus on strategies to identify metazoan replicators and the debate over their existence. I propose that we replace the concept of the replicator as a specific DNA sequence with that of a context-dependent element that is recognized by the initiator through several features, which can include DNA sequence. By embracing the complexity of replicators as being akin to that of promoter elements, future experiments can define these various features that influence the initiator-replicator interaction and address the biological significance of specifying replication-origin sites, given that site-specific initiation is dispensable for regulated genome duplication 30 . The power of predictionOne of the beauties of the replicon model was the conceptually straightforward predictions that it provided. A replicator can confer the ability to replicate onto any DNA segments that are Competing interests statement

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Chromatin regulates origin activity in Drosophila follicle cells

Cited by 244 publications

References 29 publications

Building up the Drosophila eggshell: First of all the eggshell genes must be transcribed

Building up the Drosophila eggshell: First of all the eggshell genes must be transcribed

Orchestration of chromatin-based processes: mind the TRRAP

In search of the holy replicator

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