Sunday 20 March 2005
Transcription, the initial step of gene expression, consists of converting the genetic code into a dynamic messenger RNA that will specify a required cellular function following translocation to the cytoplasm and translation.
The machineries involved in gene expression are highly conserved from yeast to metazoans. However, a fundamental difference between these organisms is that most yeast genes lack introns whereas the converse is true in higher organisms.
The TREX complex, which functions in mRNA export, unexpectedly revealed that this complex is recruited by the transcription machinery in yeast whereas the TREX complex appears to be recruited by the splicing machinery in mammals.
There is a possible conserved role for SR protein dephosphorylation in regulating the interaction between SR proteins and the mRNA export receptor TAP (Mex67 in yeast).
There is also an interesting possibility that an SR protein-TREX complex interaction is a conserved part of the mRNA export machinery.
The TREX (transcription/export) complex includes THOC1 (MIM.606930), TEX1 (MIM.606929), THO2 (MIM.300395), ALY (MIM.604171), and UAP56 (MIM.606390).
Reed R, Cheng H. TREX, SR proteins and export of mRNA. Curr Opin Cell Biol. 2005 Jun;17(3):269-73. PMID: 15901496
Darzacq X, Singer RH, Shav-Tal Y. Dynamics of transcription and mRNA export. Curr Opin Cell Biol. 2005 Jun;17(3):332-9. PMID: 15901505