High impact information on YRA1

• We identified the mRNAs that bind two conserved yeast mRNA export factors, Yra1 (refs. 1-5) and Mex67 (refs. 6,7), on a genome-wide scale and determined their level of binding [1].
• We determined that one such transcription factor, Abf1 (refs. 8-10), associates with Yra1 [1].
• Yra1 and Mex67 bind approximately 1,000 and 1,150 mRNAs, respectively, corresponding to almost 20% of the yeast genome and roughly 36% of all transcriptional events each [1].
• The essential yeast proteins Yra1 and Sub2 are messenger RNA export factors that have conserved counterparts in metazoans, designated Aly and UAP56, respectively [2].
• Hmt1 methylates Yra1 and Hrp1, two mRNA-binding proteins important for mRNA processing and export [3].

Biological context of YRA1

• Strikingly, removal of the intron from YRA1 causes a dominant-negative growth phenotype and a concomitant inhibition of mRNA export [4].
• We generated a temperature-sensitive allele of YRA1 and used it to demonstrate that cells which lack the function of both Yra1p and Yra2p are able to exit a G0 arrest and go through several rounds of cell division before arresting [5].
• Yra1p and Sub2p are components of the TREX complex, which couples transcription elongation with nuclear export of mRNAs [6].
• Conversely, Yra1 recruitment to genes without introns is not dependent on splicing [7].
• Autoregulation of the mRNA export factor Yra1p requires inefficient splicing of its pre-mRNA [8].

Physical interactions of YRA1

• Yra1p and its vertebrate homologues bind to the mRNA export factor Mex67p/TAP and are thought to play a role in mRNA export in vivo [5].

Regulatory relationships of YRA1

• These observations support the idea that Yra1p promotes mRNA export by facilitating the recruitment of Mex67p to the mRNP [9].

Other interactions of YRA1

• Together, these data indicate that the spliceosomal component Sub2p is also important in mRNA export and may function to recruit Yra1p to the mRNA [10].
• Yra1p/REF participates in mRNA export by recruiting the export receptor Mex67p to messenger ribonucleoprotein (mRNP) complexes [11].
• Additional biochemical and genetic experiments suggest a close functional relationship between Yra1p and Yra2p [5].
• Here, we report a genetic interaction between Yra1p and a conserved protein Sac3p, which previously was found to interact with Sub2p [6].
• Thus, Yra1p is the first RNA-binding protein characterized, which bridges the shuttling Mex67p/Mtr2p exporter to intranuclear mRNA transport cargoes [12].

Analytical, diagnostic and therapeutic context of YRA1

• Chromatin immunoprecipitation, FISH and pulse-chase experiments indicate that Mlps downregulate LacZ mRNA synthesis in a yra1 mutant strain [13].

References