Brl1p -- a novel nuclear envelope protein required for nuclear transport.
In this article, we identify a cold-sensitive mutant of Xpo1p designated as xop1-2 (but will be referred to from here on as xpo1-ok) that is synthetically lethal with srm1-1, a Saccharomyces cerevisiae RCC1 homolog. xpo1-ok was a novel mutated allele with a single point mutation, T283P. Suppressors of xpo1-ok were isolated, and one of them was found to encode a novel nuclear envelope integral membrane protein designated as Brl1p (Brr6 like protein no. 1). Brl1p is homologous with Brr6p at the C-terminal domain, which is well conserved in the Brr6/Brl1 family. To characterize the function of Brl1p, a series of temperature-sensitive mutants of Brl1p were isolated. All of brl1 mutations were localized to the conserved C-terminal domain that is essential for a function of Brl1p. Some brl1 alleles showed defects in nuclear export of either mRNA or protein, and nuclear pore clustering, similar to brr6-1. The cellular localization of Brl1p is also similar to that of Brr6p. The genetic analysis suggested that Brl1p functionally interacts with Brr6p. An interaction of Brl1p with Brr6p was shown by the two-hybrid method. We hypothesize that Brl1p functions for nuclear export as a complex with Brr6p.
Pubmed ID: 15882446 RIS Download
Active Transport, Cell Nucleus | Amino Acid Sequence | Biological Transport | Cell Membrane | Cell Nucleus | Cell Proliferation | DNA-Binding Proteins | Genotype | Green Fluorescent Proteins | Guanine Nucleotide Exchange Factors | In Situ Hybridization | Karyopherins | Membrane Proteins | Molecular Sequence Data | Mutation | Nuclear Envelope | Nuclear Localization Signals | Nuclear Proteins | Plasmids | Point Mutation | Protein Binding | Protein Structure, Tertiary | RNA, Messenger | Receptors, Cytoplasmic and Nuclear | Saccharomyces cerevisiae | Saccharomyces cerevisiae Proteins | Sequence Homology, Amino Acid | Signal Transduction | Temperature | Time Factors | Two-Hybrid System Techniques | beta-Galactosidase