Nuclear Organization and Dynamics of 7SK RNA in Regulating Gene Expression

Prasanth, Kannanganattu V.; Camiolo, Matthew; Chan, Grace Kar Yarn; Tripathi, Vidisha; Denis, Laurence; Nakamura, Toshio; Hübner, Michael R; Spector, David L.

doi:10.1091/mbc.e10-02-0105

Cited by 71 publications

(78 citation statements)

References 91 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To address the functional relevance of BEND3 SUMOylation and its preferential association with heterochromatic regions, we generated a triple fusion protein expressing YFP-LacI-BEND3 so that BEND3 was directly targeted to the stably integrated gene locus in 2-6-3 CLTon cells through a Lac operatorrepressor interaction. As described previously, we can activate transcription of the reporter gene at the 2-6-3 locus by addition of doxycycline, which results in decondensation of the chromatin locus, activation of transcription and finally translation of the reporter protein CFP-SKL that is targeted to the cytoplasmic peroxisomes (Janicki et al, 2004;Prasanth et al, 2010). In cells that expressed YFP-LacI constructs, addition of DOX resulted in chromatin decondensation and transcriptional activation of a reporter gene locus (Fig.…”

Section: Bend3 Can Efficiently Repress Transcriptionmentioning

confidence: 72%

“…mCherry-LacI (Lac repressor) and rtTa (reverse tetracyclinecontrolled transcriptional activator) were stably integrated in the 2-6-3 cells, so that the locus containing the transgene array could be readily visualized in living cells by the presence of mCherry-LacI and the heterochromatic locus could be decondensed upon transcriptional activation by the addition of doxycycline (DOX) in the medium (U2OS-2-6-3 CLTon, mCherry-LacI tetracycline activator; Fig. 3A) (Bernard et al, 2010;Prasanth et al, 2010;Shen et al, 2010). YFP-BEND3 localized to the heterochromatic locus in the U2OS-2-6-3 CLTon cells and showed complete colocalization with HP1b (Fig.…”

Section: Bend3 Localizes To Heterochromatin Which Is Dependent On Thmentioning

confidence: 99%

See 1 more Smart Citation

A BEN-domain-containing protein associates with heterochromatin and represses transcription

Sathyan

Shen

Tripathi

et al. 2011

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

SummaryIn eukaryotes, higher order chromatin structure governs crucial cellular processes including DNA replication, transcription and posttranscriptional gene regulation. Specific chromatin-interacting proteins play vital roles in the maintenance of chromatin structure. We have identified BEND3, a quadruple BEN domain-containing protein that is highly conserved amongst vertebrates. BEND3 colocalizes with HP1 and H3 trimethylated at K9 at heterochromatic regions in mammalian cells. Using an in vivo gene locus, we have been able to demonstrate that BEND3 associates with the locus only when it is heterochromatic and dissociates upon activation of transcription. Furthermore, tethering BEND3 inhibits transcription from the locus, indicating that BEND3 is involved in transcriptional repression through its interaction with histone deacetylases and Sall4, a transcription repressor. We further demonstrate that BEND3 is SUMOylated and that such modifications are essential for its role in transcriptional repression. Finally, overexpression of BEND3 causes premature chromatin condensation and extensive heterochromatinization, resulting in cell cycle arrest. Taken together, our data demonstrate the role of a novel heterochromatin-associated protein in transcriptional repression.

show abstract

Section: Bend3 Can Efficiently Repress Transcriptionmentioning

confidence: 72%

Section: Bend3 Localizes To Heterochromatin Which Is Dependent On Thmentioning

confidence: 99%

A BEN-domain-containing protein associates with heterochromatin and represses transcription

Sathyan

Shen

Tripathi

et al. 2011

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…1987). Using this approach, 96%-98% of 7SK RNA, which is confined to nuclei (Prasanth et al 2010), was retained within the permeabilized cells, as was most pre-tRNA-Ile (Fig. 7B).…”

Section: Packages Ncrnas From a Host Cell Surveillance Pathwaymentioning

confidence: 99%

A retrovirus packages nascent host noncoding RNAs from a novel surveillance pathway

et al. 2015

View full text Add to dashboard Cite

Although all retroviruses recruit host cell RNAs into virions, both the spectrum of RNAs encapsidated and the mechanisms by which they are recruited remain largely unknown. Here, we used high-throughput sequencing to obtain a comprehensive description of the RNAs packaged by a model retrovirus, murine leukemia virus. The major encapsidated host RNAs are noncoding RNAs (ncRNAs) and members of the VL30 class of endogenous retroviruses. Remarkably, although Moloney leukemia virus (MLV) assembles in the cytoplasm, precursors to specific tRNAs, small nuclear RNAs (snRNAs), and small nucleolar RNAs (snoRNAs) are all enriched in virions. Consistent with their cytoplasmic recruitment, packaging of both pre-tRNAs and U6 snRNA requires the nuclear export receptor Exportin-5. Adenylated and uridylated forms of these RNAs accumulate in cells and virions when the cytoplasmic exoribonuclease DIS3L2 and subunits of the RNA exosome are depleted. Together, our data reveal that MLV recruits RNAs from a novel host cell surveillance pathway in which unprocessed and unneeded nuclear ncRNAs are exported to the cytoplasm for degradation.

show abstract

“…Within this RNP complex, 7SK snRNA provides a three dimensional molecular scaffold that binds two molecules of P-TEFb to a homodimer of its inhibitory protein HEXIM1 (22)(23)(24)(25). 7SK snRNP localizes to nuclear speckles found in proximity to genomic sites of active transcription (26)(27)(28)(29). Thus, the 7SK snRNP complex provides an exchangeable pool of P-TEFb that can be readily availed to stimulate gene transcription (30).…”

Section: Introductionmentioning

confidence: 99%

Cyclin-dependent kinase 7 (CDK7)-mediated phosphorylation of the CDK9 activation loop promotes P-TEFb assembly with Tat and proviral HIV reactivation

Mbonye

Wang

Gokulrangan

et al. 2018

Journal of Biological Chemistry

View full text Add to dashboard Cite

The HIV trans-activator Tat recruits the host transcription elongation factor P-TEFb to stimulate proviral transcription. Phosphorylation of Thr186 on the activation loop (T-loop) of cyclin-dependent kinase 9 (CDK9) is essential for its kinase activity and assembly of CDK9 and cyclin T1 (CycT1) to form functional P-TEFb. Phosphorylation of a second highly conserved Tloop site, Ser175, alters the competitive binding of Tat and the host recruitment factor bromodomain containing 4 (BRD4) to P-TEFb. Here, we investigated the intracellular mechanisms that regulate these key phosphorylation events required for HIV transcription. Molecular dynamics simulations revealed that the CDK9/CycT1 interface is stabilized by intramolecular hydrogen bonding of pThr186 by an arginine triad and Glu96 of CycT1. Arginine triad substitutions that disrupted CDK9/CycT1 assembly accumulated Thr186-dephosphorylated CDK9 associated with the cytoplasmic Hsp90/Cdc37 chaperone. The Hsp90/Cdc37/CDK9 complex was also present in resting T cells, which lack CycT1. Hsp90 inhibition in primary T cells blocked P-TEFb assembly, disrupted Thr186 phosphorylation, and suppressed proviral reactivation. The selective CDK7 inhibitor THZ1 blocked CDK9 phosphorylation at Ser175, and in vitro kinase assays confirmed that CDK7 activity is principally responsible for Ser175 phosphorylation. Mutation of Ser175 to Lys had no effect on CDK9 kinase activity or P-TEFb assembly but strongly suppressed both HIV expression and BRD4 binding. We conclude that the transfer of CDK9 from the Hsp90/Cdc37 complex induced by Thr186 phosphorylation is a key step in P-TEFb biogenesis. Furthermore, we demonstrate that CDK7-mediated Ser175 phosphorylation is a downstream nuclear event essential for facilitating CDK9 T-loop interactions with Tat.http://www.jbc.org/cgi

show abstract

Nuclear Organization and Dynamics of 7SK RNA in Regulating Gene Expression

Cited by 71 publications

References 91 publications

A BEN-domain-containing protein associates with heterochromatin and represses transcription

A BEN-domain-containing protein associates with heterochromatin and represses transcription

A retrovirus packages nascent host noncoding RNAs from a novel surveillance pathway

Cyclin-dependent kinase 7 (CDK7)-mediated phosphorylation of the CDK9 activation loop promotes P-TEFb assembly with Tat and proviral HIV reactivation

Contact Info

Product

Resources

About