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Identification of an essential factor for subnuclear body.
Journal of Cell Science (Advance Online Publication)
Maeshima Laboratory, Biological Macromolecules Laboratory
Shibahara Laboratory, Division of Agricultural Genetics
The integrator complex is required for the integrity of Cajal bodies
Hideaki Takata, Hitoshi Nishijima, Kazuhiro Maeshima, Kei-ichi Shibahara
Journal of Cell Science Advance Online Publication, 2012  Journal of Cell Science doi: 10.1242/​jcs.090837

 The nucleus in eukaryotic cells is a highly organized and dynamic structure containing numerous subnuclear bodies. The morphological appearance of nuclear bodies seems to be a reflection of ongoing functions, such as DNA replication, transcription, repair, RNA processing and RNA transport. The integrator complex mediates processing of small nuclear RNA (snRNA), so it might play some roles in nuclear body formation. Here, we first show that the integrator complex is essential for Cajal body (CB) integrity. Depletion of INTS4, an integrator complex subunit, abrogated 3'-end processing of snRNA. A defect in this activity caused disassembly of CB components from CBs. These findings demonstrate that snRNA processing by the integrator complex is an essential event to maintain CB structure.
　     
Figure1

snRNAs are transcribed by RNA pol II and processed at the 3'-box by the integrator complex. The snRNAs are exported from the nucleus. In the cytoplasm, Sm proteins bind to snRNAs with SMN proteins. The snRNA complex is imported to the nucleus. This flow of newly synthesized snRNPs is required for CB integrity.