Stress-induced nuclear bodies are sites of accumulation of pre-mRNA processing factors.
Heterogeneous nuclear ribonucleoprotein (hnRNP) HAP (hnRNP A1 interacting protein) is a multifunctional protein with roles in RNA metabolism, transcription, and nuclear structure. After stress treatments, HAP is recruited to a small number of nuclear bodies, usually adjacent to the nucleoli, which consist of clusters of perichromatin granules and are depots of transcripts synthesized before stress. In this article we show that HAP bodies are sites of accumulation for a subset of RNA processing factors and are related to Sam68 nuclear bodies (SNBs) detectable in unstressed cells. Indeed, HAP and Sam68 are both present in SNBs and in HAP bodies, that we rename "stress-induced SNBs." The determinants required for the redistribution of HAP lie between residue 580 and 788. Different portions of this region direct the recruitment of the green fluorescent protein to stress-induced SNBs, suggesting an interaction of HAP with different components of the bodies. With the use of the 580-725 region as bait in a two-hybrid screening, we have selected SRp30c and 9G8, two members of the SR family of splicing factors. Splicing factors are differentially affected by heat shock: SRp30c and SF2/ASF are efficiently recruited to stress-induced SNBs, whereas the distribution of SC35 is not perturbed. We propose that the differential sequestration of splicing factors could affect processing of specific transcripts. Accordingly, the formation of stress-induced SNBs is accompanied by a change in the splicing pattern of the adenovirus E1A transcripts.
Denegri
M
M
Istituto di Genetica Biochimica ed Evoluzionistica del Consiglio Nazionale delle Richerche, Pavia 27100, Italy.
Chiodi
I
I
Corioni
M
M
Cobianchi
F
F
Riva
S
S
Biamonti
G
G
D048868:Adaptor Proteins, Signal Transducing; D017500:Adenovirus E1A Proteins / Q000235:genetics; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism*; D004268:DNA-Binding Proteins; D006367:HeLa Cells; D018869:Heat-Shock Response; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D012322:RNA Precursors / Q000378:metabolism*; D012326:RNA Splicing; D012333:RNA, Messenger; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D000068103:Serine-Arginine Splicing Factors
D048868:Adaptor Proteins, Signal Transducing; D017500:Adenovirus E1A Proteins; D004268:DNA-Binding Proteins; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C489559:KHDRBS1 protein, human; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D010750:Phosphoproteins; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D012261:Ribonucleoproteins; C073288:SRSF2 protein, human; D000068103:Serine-Arginine Splicing Factors