Structure of the Sac3 RNA-binding M-region in the Saccharomyces cerevisiae TREX-2 complex.
Nucleic Acids Res
; 45(9): 5577-5585, 2017 May 19.
Article
em En
| MEDLINE
| ID: mdl-28334829
Transcription-export complex 2 (TREX-2, or THSC) facilitates localization of actively transcribing genes such as GAL1 to the nuclear periphery, contributes to the generation of export-competent mRNPs and influences gene expression through interactions with Mediator. TREX-2 is based on a Sac3 scaffold to which Thp1, Sem1, Cdc31 and Sus1 bind and consists of three modules: the N-region (Sac3â¼1-100), which binds mRNA export factor Mex67:Mtr2; the M-region, in which Thp1 and Sem1 bind to Sac3â¼100-550; and the CID region in which Cdc31 and two Sus1 chains bind to Sac3â¼720-805. Although the M-region of Sac3 was originally thought to encompass residues â¼250-550, we report here the 2.3Å resolution crystal structure of a complex containing Sac3 residues 60-550 that indicates that the TPR-like repeats of the M-region extend to residue 137 and that residues 90-125 form a novel loop that links Sac3 to Thp1. These new structural elements are important for growth and mRNA export in vivo. Although deleting Sac3 residues 1-90 produced a wild-type phenotype, deletion of the loop as well generated growth defects at 37°C, whereas the deletion of residues 1-250 impaired mRNA export and also generated longer lag times when glucose or raffinose was replaced by galactose as the carbon source.
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Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
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RNA Fúngico
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Proteínas de Saccharomyces cerevisiae
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Complexos Multiproteicos
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article