English Title: Structural characterization of a protein/RNA complex : human TAP/NXF1 protein/retroviral CTE RNA
Abstract Eukaryotic gene expression involves several steps, including transcription, post-transcriptional processing of pre-mRNA transcripts and export of the correctly processed mRNAs from the nucleus to the cytoplasm, where translation takes place. Evidence has accumulated suggesting that these steps are both functionally and physically coupled by protein-protein interactions, involving proteins that bind the mRNA, packing it into ribonucleoprotein particles (mRNPs). In humans, the protein TAP/NXF1 interacts with mRNA export cargoes and mediates their nuclear export by shuttling through nuclear pore complexes (NPCs). TAP is a multidomain modular protein composed of an N-terminal mRNP-binding region and a C-terminal NPC-binding region. TAP is believed to contact the cellular mRNA indirectly via protein adaptors such as REF/Aly. It can also mediate the nuclear export of exogenous and partially processed viral mRNAs containing a cis-acting Constitutive Transport Element (CTE), which is the case for some types of simian retroviruses. The CTE RNA binds directly to the N-terminal region of TAP and accesses the cellular mRNA export pathway, skipping several upstream events of the mRNA maturation process (e.g. splicing). The purpose of this work is to characterise the surface and mode of interaction of TAP N-terminal with the CTE RNA and some of its putative cellular adaptors, in particular the mammalian protein REF/Aly. Given this information, we hope to advance in understanding how TAP couples late stages of pre-mRNA processing and mRNA nuclear export. We have used for this purpose, X-ray crystallography and multidimensional NMR spectroscopy, in combination with small angle X-ray scattering experiments.
|Supervisor:||Elena Conti, Dr.|
|Date of thesis defense:||4 October 2004|
|Faculties / Institutes:||Service facilities > Heidelberg University Biochemistry Center|
|Subjects:||570 Life sciences|
|Controlled Keywords:||TAP, CTE RNA, NMR, X-ray|