Nuclear export of signal recognition particle RNA in mammalian cells.
In mammalian cells the signal recognition particle (SRP) consists of a approximately 300 nucleotide RNA and six proteins. Although the molecular structure and functional cycle of the SRP are both very well understood, far less is known about how the SRP is first assembled in the cell. Recent work has suggested that SRP assembly begins in the nucleoli. When NRK (rat fibroblast) cells were treated with leptomycin B (LMB), a specific inhibitor of the CRM1 nuclear export receptor, the level of SRP RNA increased in the nucleoli, as did the level of nucleolar 28S ribosomal RNA. Moreover, when a hamster cell line carrying a temperature-sensitive mutation in the guanine nucleotide exchange factor of the GTPase Ran (Ran-GEF) was shifted to the non-permissive temperature, the nucleolar level of SRP RNA increased. These results indicate that the steady-state concentration of SRP RNA in the nucleolus is sensitive to perturbations in nuclear import/export pathways.
Alavian
Christina N
CN
Department of Biochemistry and Molecular Pharmacology and Program in Cell Dynamics, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Politz
Joan C Ritland
JC
Lewandowski
Laura B
LB
Powers
Christine M
CM
Pederson
Thoru
T
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000818:Animals; D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism; D006224:Cricetinae; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D009154:Mutation; D015345:Oligonucleotide Probes; D012313:RNA / Q000378:metabolism*; D012339:RNA, Ribosomal, 28S / Q000378:metabolism; D051381:Rats; D018271:Signal Recognition Particle / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D020931:ran GTP-Binding Protein / Q000378:metabolism
D005231:Fatty Acids, Unsaturated; D020662:Guanine Nucleotide Exchange Factors; D015345:Oligonucleotide Probes; D012339:RNA, Ribosomal, 28S; D018271:Signal Recognition Particle; D012313:RNA; D020931:ran GTP-Binding Protein; C038753:leptomycin B