Locations of chromosomal proteins in polytene chromosomes.

Alfageme, Candido Rodriguez; Rudkin, George T.; Cohen, Lisa R.

doi:10.1073/pnas.73.6.2038

Cited by 92 publications

(29 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In agreement with this work, a heterochromatic localization was observed for D1 in both mitotic and interphase diploid cells by immunostaining (Renner et al 2000; 1 Aulner et al 2002). As revealed by immunostaining to salivary gland polytene chromosomes, D1 shows a less predominant localization to euchromatic sites, which could reflect its binding to interspersed AT tracts (Alfageme et al 1976;Rodriguez Alfageme et al 1980). Mutant alleles of the D1 gene have not been isolated in phenotype-based genetic screens.…”

supporting

confidence: 69%

The Multi-AT-Hook Chromosomal Protein of Drosophila melanogaster, D1, Is Dispensable for Viability

Weiler

Chatterjee

2009

Genetics

View full text Add to dashboard Cite

The D1 protein is a high mobility group A (HMGA)-like nonhistone chromosomal protein with primary localization to certain AT-rich satellite DNA sequences within heterochromatin. The binding of D1 to euchromatic sequences is less studied and the functional significance of its chromosomal associations is unclear. By taking advantage of existing P-insertion alleles of the D1 gene, I generated D1 null mutations to investigate the phenotypic effect of loss of the D1 gene. In contrast to a previous report, I determined that the D1 gene is not essential for viability of Drosophila melanogaster, and moreover, that loss of D1 has no obvious phenotypic effects. My tests for an effect of D1 mutations on PEV revealed that it is not a suppressor of variegation, as concluded by other investigators. In fact, the consequence of loss of D1 on one of six variegating rearrangements tested, T(2;3)Sb V , was dominant enhancement of PEV, suggesting a role for the protein in euchromatic chromatin structure and/or transcription. A study of D1 protein sequence conservation highlighted features shared with mammalian HMGA proteins, which function as architectural transcription factors.

show abstract

supporting

confidence: 69%

The Multi-AT-Hook Chromosomal Protein of Drosophila melanogaster, D1, Is Dispensable for Viability

Weiler

Chatterjee

2009

Genetics

View full text Add to dashboard Cite

show abstract

“…RNase treatment of chromosomes was carried out in situ in the salivary glands. Briefly, dissected glands were incubated at room temperature with the appropriate RNase in Cohen Buffer (Alfageme et al 1976) for 10 min. Ribonuclease digest concentrations were DNase-free RNase A (10 µg/mL; Promega Corp.), recombinant RNase H (0.05 U/µL; Ambion, Inc.), and recombinant RNase III (0.05 U/µL; New England Biolabs).…”

Section: Embryo Preparation Polytene Chromosome Preparation and Rnamentioning

confidence: 99%

Drosophila PIWI associates with chromatin and interacts directly with HP1a

Brower-Toland¹,

Findley²,

Jiang³

et al. 2007

Genes Dev.

318

297

View full text Add to dashboard Cite

The interface between cellular systems involving small noncoding RNAs and epigenetic change remains largely unexplored in metazoans. RNA-induced silencing systems have the potential to target particular regions of the genome for epigenetic change by locating specific sequences and recruiting chromatin modifiers. Noting that several genes encoding RNA silencing components have been implicated in epigenetic regulation in Drosophila, we sought a direct link between the RNA silencing system and heterochromatin components. Here we show that PIWI, an ARGONAUTE/PIWI protein family member that binds to Piwi-interacting RNAs (piRNAs), strongly and specifically interacts with heterochromatin protein 1a (HP1a), a central player in heterochromatic gene silencing. The HP1a dimer binds a PxVxL-type motif in the N-terminal domain of PIWI. This motif is required in fruit flies for normal silencing of transgenes embedded in heterochromatin. We also demonstrate that PIWI, like HP1a, is itself a chromatin-associated protein whose distribution in polytene chromosomes overlaps with HP1a and appears to be RNA dependent. These findings implicate a direct interaction between the PIWI-mediated small RNA mechanism and heterochromatin-forming pathways in determining the epigenetic state of the fly genome.[Keywords: PIWI; ARGONAUTE; HP1; heterochromatin; epigenetic; RNAi] Supplemental material is available at http://www.genesdev.org. . In TGS, small RNAs are incorporated into specialized effector complexes able to regulate chromatin modification, resulting in reduced access for the transcriptional machinery to chromatin. The TGS system that contributes to initiation and maintenance of heterochromatin formation in Schizosaccharomyces pombe is particularly well characterized (Verdel and Moazed 2005;Grewal and Jia 2007). In S. pombe, the RNA silencing system targets histone 3 Lys 9 (H3K9) methylation and recruits HP1 homolog Swi6 to the MAT locus and to repetitive elements in pericentric heterochromatin, setting up a heterochromatin spreading/maintenance loop that is dependent on the interaction of Swi6 with the Clr4 histone methyltransferase (HMT) (Grewal and Jia 2007). In plants, a specialized small RNA pathway utilizes heterochromatic RNAs to direct DNA methylation and presumably other chromatin modifications to effect silencing of target loci (for review, see Vaucheret 2007). In Caenorhabditis elegans, a single episode of RNA interference (RNAi) exposure can induce silencing inherited over many generations; mutations that abolish inheritance are all involved in chromatin structure, suggesting a chromatin-based mechanism (Vastenhouw et al. 2006). While the work in fission yeast and plants provides a possible paradigm for RNAi-dependent TGS in metazoans, a specialized TGS effector complex has not yet been characterized in an animal.

show abstract

“…It is possible to localize proteins in these chromosomes and thereby obtain some information as to the biological processes in which the given proteins might be involved. In order to visualize the chromosomal proteins, the method of indirect immunofluorescence was developed several years ago (7,8). The distribution patterns of a number of chromosomal proteins of unknown function have been determined by this approach (8-11).…”

Section: Introductionmentioning

confidence: 99%

Drosophila DNA topoisomerase I is associated with transcriptionally active regions of the genome.

Fleischmann¹,

Pflugfelder²,

Steiner³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

192

View full text Add to dashboard Cite

The distribution of DNA topoisomerase I within Drosophila polytene chromosomes was observed by immunofluorescent staining with affinity-purified antibodies. The enzyme is preferentially associated with active loci, as shown by prominent staining of puffs. The heat shock loci 87A-87C are stained after, but not before, heat shock induction. A detailed comparison of the distribution of topoisomerase I with that of RNA polymerase II reveals a similar, al, though not identical, pattern of association. Topoisomerase I is also found in association with the nucleolus, the site of transcription by RNA polymerase I.The polytene chromosomes of the Drosophila salivary gland provide an excellent system for investigating the distribution of specific chromosomal proteins. Although highly organized, these giant chromosomes behave like diploid interphase chromatin in many assays of function and fine structure (1-6). They can, however, be easily observed under the light microscope; some substructure, such as transcriptionally active sites, can be recognized. It is possible to localize proteins in these chromosomes and thereby obtain some information as to the biological processes in which the given proteins might be involved. In order to visualize the chromosomal proteins, the method of indirect immunofluorescence was developed several years ago (7,8). The distribution patterns of a number of chromosomal proteins of unknown function have been determined by this approach (8-11). The method has allowed identification of a subclass of nonhistone chromosomal proteins that are prominently associated with loci that are active or inducible at some time in the salivary glands of the third instar larvae and prepupae (10,12,13).In addition, distribution patterns of proteins of known function have been analyzed-e.g., RNA polymerase 11 (14-17) and ribonucleoproteins (18). These proteins are preferentially associated with the transcriptionally active regions of the genome. In this paper we report the distribution pattern of DNA topoisomerase I. This enzyme is well characterized at the molecular level, but the range of its biological functions in eukaryotes has yet to be established (for reviews, see refs. 19-25). The ability of eukaryotic topoisomerase I to relax either negatively or positively supercoiled DNA hints that the enzyme might play a role in gene activation, either effecting structural changes in chromatin as it assumes a more "open" conformation (e.g., as detected by the appearance of puffs) and/or facilitating transcription per se (26, 27). There is some evidence in favor of a role of topoisomerase in transcription. For example, topoisomerase has been shown to be associated with ribosomal gene chromatin actively expressing rRNA (28); topoisomerase I is recovered with nucleosomes in a fraction enriched for transcriptionally active genes (29). Complex formation between eukaryotic DNA topoisomerase I and chromosomal high mobility group proteins and histone H1 has also been reported (30). However, there has been no direct evi...

show abstract

Locations of chromosomal proteins in polytene chromosomes.

Cited by 92 publications

References 36 publications

The Multi-AT-Hook Chromosomal Protein of Drosophila melanogaster, D1, Is Dispensable for Viability

The Multi-AT-Hook Chromosomal Protein of Drosophila melanogaster, D1, Is Dispensable for Viability

Drosophila PIWI associates with chromatin and interacts directly with HP1a

Drosophila DNA topoisomerase I is associated with transcriptionally active regions of the genome.

Contact Info

Product

Resources

About