mRNA stability, mRNA translation and spatial localization of mRNA species within a cell can be governed by signals in the 3′-UTR (3′-untranslated region). Local translation of proteins is essential for the development of many eukaryotic cell types, such as the Drosophila embryo, where the spatial and temporal localization of bicoid and gurken mRNAs, among others, is required to establish morphogen gradients. More recent studies have suggested that mRNA localization also occurs with transcripts coding for membrane-based or secreted proteins, and that localization at organelles such as the endoplasmic reticulum directs translation more efficiently to specific subdomains, so as to aid correct protein localization. In human epithelial cells, the mRNA coding for SGLT1 (sodium–glucose co-transporter 1), an apical membrane protein, has been shown to be localized apically in polarized cells. However, the nature of the signals and RNA-binding proteins involved are unknown. Ongoing work is aimed at identifying the localization signals in the SGLT1 3′-UTR and the corresponding binding proteins. Using a protein extract from polarized Caco-2 cells, both EMSAs (electrophoretic mobility-shift assays) and UV cross-linking assays have shown that a specific protein complex is formed with the first 300 bases of the 3′-UTR sequence. MFold predictions suggest that this region folds into a complex structure and ongoing studies using a series of strategic deletions are being carried out to identify the precise nature of the motif involved, particularly the role of the sequence or RNA secondary structure, as well as to identify the main proteins present within the complex. Such information will provide details of the post-transcriptional events that lead to apical localization of the SGLT1 transcript and may reveal mechanisms of more fundamental importance in the apical localization of proteins in polarized epithelia.
Skip Nav Destination
Article navigation
June 2008
- Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
Conference Article|
May 21 2008
Targeting of transcripts encoding membrane proteins in polarized epithelia: RNA–protein binding studies of the SGLT1 3′-UTR
Christopher M. Pedder;
Christopher M. Pedder
1Institute for Cell and Molecular Biosciences, Newcastle University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, U.K.
Search for other works by this author on:
Dianne Ford;
Dianne Ford
1Institute for Cell and Molecular Biosciences, Newcastle University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, U.K.
Search for other works by this author on:
John E. Hesketh
John E. Hesketh
1
1Institute for Cell and Molecular Biosciences, Newcastle University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, U.K.
1To whom correspondence should be addressed (email j.e.hesketh@ncl.ac.uk).
Search for other works by this author on:
Biochem Soc Trans (2008) 36 (3): 525–527.
Article history
Received:
January 18 2008
Citation
Christopher M. Pedder, Dianne Ford, John E. Hesketh; Targeting of transcripts encoding membrane proteins in polarized epithelia: RNA–protein binding studies of the SGLT1 3′-UTR. Biochem Soc Trans 1 June 2008; 36 (3): 525–527. doi: https://doi.org/10.1042/BST0360525
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.