Structural and functional characterization of noncoding repetitive RNAs transcribed in stressed human cells.
Thermal and chemical stresses induce the formation in human cells of novel and transient nuclear structures called nuclear stress bodies (nSBs). These contain heat shock factor 1 (HSF-1) and a specific subset of pre-mRNA processing factors. Nuclear stress bodies are assembled on specific pericentromeric heterochromatic domains containing satellite III (SatIII) DNA. In response to stress, these domains change their epigenetic status from heterochromatin to euchromatin and are transcribed in poly-adenylated RNAs that remain associated with nSBs. In this article, we describe the cloning, sequencing, and functional characterization of these transcripts. They are composed of SatIII repeats and originate from the transcription of multiple sites within the SatIII arrays. Interestingly, the level of SatIII RNAs can be down-regulated both by antisense oligonucleotides and small interfering RNAs (siRNA). Knockdown of SatIII RNA by siRNAs requires the activity of Argonaute 2, a component of the RNA-induced silencing complex. Down-regulation of satellite III RNAs significantly affects the recruitment of RNA processing factors to nSBs without altering the association of HSF-1 with these structures nor the presence of acetylated histones within nSBs. Thus, satellite III RNAs have a major role in the formation of nSBs.
Valgardsdottir
Rut
R
Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, 27100 Pavia, Italy.
Chiodi
Ilaria
I
Giordano
Manuela
M
Cobianchi
Fabio
F
Riva
Silvano
S
Biamonti
Giuseppe
G
D000818:Animals; D060565:Argonaute Proteins; D002459:Cell Fusion; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D022003:Cell Nucleus Structures / Q000378:metabolism*; D018920:Coculture Techniques; D004276:DNA, Satellite / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D022041:Euchromatin / Q000235:genetics / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2; D006367:HeLa Cells; D000076249:Heat Shock Transcription Factors; D018869:Heat-Shock Response; D006570:Heterochromatin / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010448:Peptide Initiation Factors / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D022661:RNA, Untranslated / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D034743:RNA-Induced Silencing Complex; D017423:Sequence Analysis, RNA; D013312:Stress, Physiological / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors; D014158:Transcription, Genetic
C466422:AGO2 protein, human; D060565:Argonaute Proteins; D004276:DNA, Satellite; D004268:DNA-Binding Proteins; D022041:Euchromatin; D015852:Eukaryotic Initiation Factor-2; D000076249:Heat Shock Transcription Factors; D006570:Heterochromatin; D016376:Oligonucleotides, Antisense; D010448:Peptide Initiation Factors; D034741:RNA, Small Interfering; D022661:RNA, Untranslated; D034743:RNA-Induced Silencing Complex; D014157:Transcription Factors