Processing of Pre-mRNA in Polytene Nuclei ofChironomus tentansSalivary Gland Cells

Wieslander, Lars; Baurén, Göran; Bernholm, Kerstin; Jiang, Wei‐Qin; Wetterberg, Ingela

doi:10.1006/excr.1996.0366

Cited by 7 publications

(5 citation statements)

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“…The fact that perichromatin fibrils are the only nucleoplasmic structural constituent containing rapidly labelled RNA, as well as all transcription and processing factors, strongly support that they are also the site where most pre-mRNA processing steps take place. This is also in line with previously reported observations (see, for example, Fakan et al 1986;Beyer and Osheim 1988;Wieslander et al 1996) suggesting that pre-mRNA splicing occurs co-transcriptionally.…”

Section: Dna Replicationsupporting

confidence: 92%

The functional architecture of the nucleus as analysed by ultrastructural cytochemistry

Fakan

2004

Histochem Cell Biol

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Ultrastructural cytochemistry has been, for many years now, a major tool for investigating structure-function relationships in the cell nucleus. It has been essential in approaching the roles which different nuclear structural constituents can play in nuclear functions. This article briefly summarises transmission electron microscopic studies aimed at characterising in situ nuclear architectural domains and their involvement in main nuclear functions, such as DNA replication, hnRNA transcription and pre-mRNA processing. It discusses the importance of ultrastructural cytochemistry in high resolution analyses of intranuclear distribution of chromatin domains and their topological relationships with other structural interphase nuclear constituents. It puts forward the central role of the perichromatin region as a functional nuclear domain. Finally, it attempts to critically evaluate some future applications of ultrastructural investigations of the nucleus and stresses the importance of combining them with light microscopic analyses of living cells.

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Section: Dna Replicationsupporting

confidence: 92%

The functional architecture of the nucleus as analysed by ultrastructural cytochemistry

Fakan

2004

Histochem Cell Biol

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“…In spite of the fact that the general organization of the polytene nuclei differs from that of diploid nuclei, the basic processes of gene expression are the same in both types of cells (reviewed in refs. 32 and 33). We have used the advantages that polytene nuclei offer for in situ studies of gene expression to analyze the association of profilin with chromatin.…”

Section: Discussionmentioning

confidence: 99%

Profilin is associated with transcriptionally active genes

Söderberg

Hessle²,

Euler³

et al. 2012

Nucleus

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We have raised antibodies against the profilin of Chironomus tentans to study the location of profilin relative to chromatin and to active genes in salivary gland polytene chromosomes. We show that a fraction of profilin is located in the nucleus, where profilin is highly concentrated in the nucleoplasm and at the nuclear periphery. Moreover, profilin is associated with multiple bands in the polytene chromosomes. By staining salivary glands with propidium iodide, we show that profilin does not co-localize with dense chromatin. Profilin associates instead with protein-coding genes that are transcriptionally active, as revealed by co-localization with hnRNP and snRNP proteins. We have performed experiments of transcription inhibition with actinomycin D and we show that the association of profilin with the chromosomes requires ongoing transcription. However, the interaction of profilin with the gene loci does not depend on RNA. Our results are compatible with profilin regulating actin polymerization in the cell nucleus. However, the association of actin with the polytene chromosomes of C. tentans is sensitive to RNase, whereas the association of profilin is not, and we propose therefore that the chromosomal location of profilin is independent of actin.

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“…The Balbiani ring (BR) genes of C. tentans code for large secretory proteins in the salivary glands of the Chironomus larvae (for review, see Wieslander 1994). The BR pre-mRNAs have all the features of protein-coding transcripts and undergo typical premRNA processing (for review, see Wieslander et al 1996;Kiesler and Visa 2004). The BR genes can be identified in polytene chromosome preparations, and by using immunoelectron microscopy (immuno-EM) it is possible to study the association of specific proteins with the newly synthesized BR pre-mRNAs at the site of transcription and on the way to the nuclear pores.…”

Section: Introductionmentioning

confidence: 99%

Rrp6 is recruited to transcribed genes and accompanies the spliced mRNA to the nuclear pore

Hessle

Euler²,

Valdivia

et al. 2012

RNA

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Rrp6 is an exoribonuclease involved in the quality control of mRNA biogenesis. We have analyzed the association of Rrp6 with the Balbiani ring pre-mRNPs of Chironomus tentans to obtain insight into the role of Rrp6 in splicing surveillance. Rrp6 is recruited to transcribed genes and its distribution along the genes does not correlate with the positions of exons and introns. In the nucleoplasm, Rrp6 is bound to both unspliced and spliced transcripts. Rrp6 is released from the mRNPs in the vicinity of the nuclear pore before nucleo-cytoplasmic translocation. We show that Rrp6 is associated with newly synthesized transcripts during all the nuclear steps of gene expression and is associated with the transcripts independently of their splicing status. These observations suggest that the quality control of pre-mRNA splicing is not based on the selective recruitment of the exoribonuclease Rrp6 to unprocessed mRNAs.

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Processing of Pre-mRNA in Polytene Nuclei ofChironomus tentansSalivary Gland Cells

Cited by 7 publications

References 0 publications

The functional architecture of the nucleus as analysed by ultrastructural cytochemistry

The functional architecture of the nucleus as analysed by ultrastructural cytochemistry

Profilin is associated with transcriptionally active genes

Rrp6 is recruited to transcribed genes and accompanies the spliced mRNA to the nuclear pore

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