The growing pre-mRNA recruits actin and chromatin-modifying factors to transcriptionally active genes.
In the dipteran Chironomus tentans, actin binds to hrp65, a nuclear protein associated with mRNP complexes. Disruption of the actin-hrp65 interaction in vivo by the competing peptide 65-2CTS reduces transcription drastically, which suggests that the actin-hrp65 interaction is required for transcription. We show that the inhibitory effect of the 65-2CTS peptide on transcription is counteracted by trichostatin A, a drug that inhibits histone deacetylation. We also show that actin and hrp65 are associated in vivo with p2D10, an evolutionarily conserved protein with histone acetyltransferase activity that acts on histone H3. p2D10 is recruited to class II genes in a transcription-dependent manner. We show, using the Balbiani ring genes of C. tentans as a model system, that p2D10 is cotranscriptionally associated with the growing pre-mRNA. We also show that experimental disruption of the actin-hrp65 interaction by the 65-2CTS peptide in vivo results in the release of p2D10 from the transcribed genes, reduced histone H3 acetylation, and a lower level of transcription activity. Furthermore, antibodies against p2D10 inhibit run-on elongation. Our results suggest that actin, hrp65, and p2D10 are parts of a positive feedback mechanism that contributes to maintaining the active transcription state of a gene by recruiting HATs at the RNA level.
Sjölinder
Mikael
M
Department of Molecular Biology and Functional Genomics, The Wenner-Gren Institute, Stockholm University, Sweden.
Björk
Petra
P
Söderberg
Emilia
E
Sabri
Nafiseh
N
Farrants
Ann-Kristin Ostlund
AK
Visa
Neus
N
D000123:Acetyltransferases / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002683:Chironomidae / Q000235:genetics / Q000254:growth & development; D002843:Chromatin / Q000378:metabolism*; D004258:DNA Polymerase III / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D051548:Histone Acetyltransferases; D019476:Insect Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism; D012322:RNA Precursors / Q000502:physiology*; D012333:RNA, Messenger / Q000502:physiology*; D016601:RNA-Binding Proteins; D019474:Transcription Factors, TFIII / Q000276:immunology / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology*; D000098832:Transcription Factor TFIIIC
D000199:Actins; D000906:Antibodies; D002843:Chromatin; D019476:Insect Proteins; D009687:Nuclear Proteins; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D019474:Transcription Factors, TFIII; C404122:hrp65 protein, Chironomus tentans; D000098832:Transcription Factor TFIIIC; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; D012319:RNA Polymerase II; D004258:DNA Polymerase III