FLASH, a proapoptotic protein involved in activation of caspase-8, is essential for 3' end processing of histone pre-mRNAs.
3' end processing of histone pre-mRNA requires U7 snRNP, which binds downstream of the cleavage site and recruits the endonuclease CPSF-73. U7 snRNP contains a unique Sm ring in which the canonical SmD2 protein is replaced by Lsm11. We used the yeast two-hybrid system to identify binding partners of Lsm11 and selected the proapoptotic protein FLASH. Human FLASH interacts with Lsm11 in vitro and stimulates 3' end processing of histone pre-mRNA in mammalian nuclear extracts. We also identified the FLASH ortholog in Drosophila and demonstrate that it interacts with Lsm11 in vitro and in vivo. Drosophila FLASH localizes to histone locus bodies, and its depletion from fly cells inhibits U7-dependent processing, resulting in polyadenylation of histone mRNAs. These results demonstrate that FLASH is an essential factor required for 3' end maturation of histone mRNAs in both vertebrates and invertebrates and suggest a potential link between this process and apoptosis.
Yang
Xiao-Cui
XC
Department of Biochemistry and Biophysics and Program in Molecular Biology and Biotechnology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Burch
Brandon D
BD
Yan
Yan
Y
Marzluff
William F
WF
Dominski
Zbigniew
Z
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000378:metabolism; D004789:Enzyme Activation; D017930:Genes, Reporter; D006657:Histones / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D026723:Polyadenylation; D011485:Protein Binding; D021381:Protein Transport; D026721:RNA 3' End Processing / Q000235:genetics*; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques
D051017:Apoptosis Regulatory Proteins; D002135:Calcium-Binding Proteins; D053181:Caspase 8; D029721:Drosophila Proteins; D006657:Histones; D012322:RNA Precursors; D016601:RNA-Binding Proteins; C485604:CASP8AP2 protein, human; C506080:LSM11 protein, human