Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes

Scheer, Ulrich; Hinssen, Horst; Franke, Werner W.; Jockusch, Brigitte M.

doi:10.1016/0092-8674(84)90196-x

Cited by 283 publications

(167 citation statements)

References 65 publications

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“…In their experiments, Triturus oocytes, still in the ovary, regained their normal structure 1-2 d after removal of the inhibitor. Later studies by Scheer and his colleagues (Scheer, 1987;Scheer et al, 1984) showed that isolated oocytes could also recover from the effects of actinomycin when incubated 1-2 d in a medium without the inhibitor. Similarly, lampbrush chromosomes can recover their normal structure after y-ray treatment (Loones, 1979) or after heat shock, either in vitro (Flannery and Hill, 1988) or in vivo (Rodriguez-Martin et al, 1989).…”

Section: Discussionmentioning

confidence: 99%

Transcription on lampbrush chromosome loops in the absence of U2 snRNA.

Tsvetkov

Jantsch

et al. 1992

MBoC

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The five small nuclear RNAs (snRNAs) involved in splicing occur on the loops of amphibian lampbrush chromosomes and in hundreds to thousands of extrachromosomal granules called B snurposomes. To assess the role of these snRNAs during transcription and to explore possible relationships between the loops and B snurposomes, we injected singlestranded antisense oligodeoxynucleotides (oligos) against Ul and U2 snRNA into toad and newt oocytes. As shown before, antisense Ul and U2 oligos caused truncation of Ul and complete destruction of U2 snRNAs, respectively. However, injection of any oligo, regardless of sequence, brought on dramatic cytological changes, including shortening of the chromosomes and retraction of the lateral loops, with concomitant shutdown of polymerase II transcription, as well as disappearance of some or all of the B snurposomes. When injected oocytes were incubated for 12 h or longer in physiological saline, these changes were reversible; that is, the chromosomes lengthened, transcription (detected by 3H-UTP incorporation) resumed on newly extended lateral loops, and B snurposomes reappeared. In situ hybridization showed that loops and B snurposomes had negligible amounts of U2 snRNA after recovery from injection of the anti-U2 oligo, whereas these structures had normal levels of U2 snRNA after recovery from a control oligo. Thus, the morphological integrity of B snurposomes and lampbrush chromosome loops is not dependent on the presence of U2 snRNA. Because transcription occurs in the absence of U2 snRNA, we conclude that splicing is not required for transcription on lampbrush chromosome loops.

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Section: Discussionmentioning

confidence: 99%

Transcription on lampbrush chromosome loops in the absence of U2 snRNA.

Tsvetkov

Jantsch

et al. 1992

MBoC

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“…The presence of ␤-actin in the nucleus was documented for the first time many years ago (Egly et al, 1984;Scheer et al, 1984), but the connection between ␤-actin and gene transcription has only recently been demonstrated (Olave et al, 2002;Pederson and Aebi, 2002;Fomproix and Percipalle, 2004;Grummt, 2006;Jockusch et al, 2006;Percipalle and Visa, 2006;Obrdlik et al, 2007). Nuclear ␤-actin associates with components of the ATP-dependent chromatin-remodeling complexes (Olave et al, 2002;Bettinger et al, 2004), with RNP particles (Percipalle and Visa, 2006), and with the three RNA polymerases in the eukaryotic cell nucleus, both in vitro and in vivo (Hu et al, 2004;Philimonenko et al, 2004;Kukalev et al, 2005;Wu et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Induction of HoxB Transcription by Retinoic Acid Requires Actin Polymerization

Ferrai

Naum-Onganía

Longobardi

et al. 2009

MBoC

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We have analyzed the role of actin polymerization in retinoic acid (RA)-induced HoxB transcription, which is mediated by the HoxB regulator Prep1. RA induction of the HoxB genes can be prevented by the inhibition of actin polymerization. Importantly, inhibition of actin polymerization specifically affects the transcription of inducible Hox genes, but not that of their transcriptional regulators, the RARs, nor of constitutively expressed, nor of actively transcribed Hox genes. RA treatment induces the recruitment to the HoxB2 gene enhancer of a complex composed of "elongating" RNAPII, Prep1, ␤-actin, and N-WASP as well as the accessory splicing components p54Nrb and PSF. We show that inhibition of actin polymerization prevents such recruitment. We conclude that inducible Hox genes are selectively sensitive to the inhibition of actin polymerization and that actin polymerization is required for the assembly of a transcription complex on the regulatory region of the Hox genes.

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“…A ctin and myosin I are present not only in the cytoplasm but also in the cell nucleus (1,2), where they have been implicated in transcription of protein-coding genes (3)(4)(5) and nuclear export (6). Many other cytoskeletal components have also been found in the cell nucleus, and some of them have been tentatively implicated in gene expression (reviewed in ref.…”

mentioning

confidence: 99%

An actin–ribonucleoprotein interaction is involved in transcription by RNA polymerase II

Percipalle

Fomproix

Kylberg

et al. 2003

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

129

107

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To determine the function of actin in the cell nucleus, we sought to identify nuclear actin-binding proteins in the dipteran Chironomus tentans using DNase I-affinity chromatography. We identified the RNA-binding protein hrp65 as an actin-binding protein and showed that the C-terminal sequence of the hrp65-2 isoform is able to interact directly with actin in vitro. In vivo crosslinking and coimmunoprecipitation experiments indicated that hrp65 and actin are also associated in the living cell. Moreover, in vivo administration of a competing peptide corresponding to the C-terminal sequence of hrp65-2 disrupted the actin-hrp65-2 interaction and caused a specific and drastic reduction of transcription as judged by puff regression and diminished bromo-UTP incorporation. Our results indicate that an actin-based mechanism is implicated in the transcription of most if not all RNA polymerase II genes and suggest that an actin-hrp65-2 interaction is required to maintain the normal transcriptional activity of the cell. Furthermore, immunoelectron microscopy experiments and nuclear run-on assays suggest that the actin-hrp65-2 complex plays a role in transcription elongation.A ctin and myosin I are present not only in the cytoplasm but also in the cell nucleus (1, 2), where they have been implicated in transcription of protein-coding genes (3-5) and nuclear export (6). Many other cytoskeletal components have also been found in the cell nucleus, and some of them have been tentatively implicated in gene expression (reviewed in ref. 1).Actin has been found associated with (pre)-messenger ribonucleoprotein (pre-mRNP) complexes in a variety of organisms, and we recently revealed that actin is a bona fide component of the Balbiani ring (BR) pre-mRNP particles in the salivary gland cells of the dipteran Chironomus tentans (7). The BR genes code for large secretory proteins that are expressed in the salivary gland cells of C. tentans (reviewed in ref. 8). The BR pre-mRNAs are assembled into large RNP particles, the BR pre-mRNPs, that can be visualized directly by transmission electron microscopy (reviewed in ref. 9). Actin is incorporated cotranscriptionally into the newly synthesized BR pre-mRNPs by binding to a subset of heterogeneous nuclear RNP (hnRNP) proteins such as the hnRNP A1-like protein hrp36 (7). Remarkably, the presence of actin in RNP complexes is not restricted to the BR particles of C. tentans, because actin has also been found associated with certain hnRNP proteins of the A͞B group in mammalian pre-mRNPs (10).The presence of actin in the cell nucleus is well documented, but the precise role of nuclear actin is still not understood. To obtain further insight into the function(s) of nuclear actin, we sought to identify additional proteins of C. tentans that bind to actin in the cell nucleus. Materials and MethodsDetailed descriptions of the materials and methods can be found in Supporting Materials and Methods, which is published as supporting information on the PNAS web site, www.pnas.org.DNase I-Sepharose Pull-Down...

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Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes

Cited by 283 publications

References 65 publications

Transcription on lampbrush chromosome loops in the absence of U2 snRNA.

Transcription on lampbrush chromosome loops in the absence of U2 snRNA.

Induction of HoxB Transcription by Retinoic Acid Requires Actin Polymerization

An actin–ribonucleoprotein interaction is involved in transcription by RNA polymerase II

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