Dear Glycobiologist colleagues:
A graduate student in a neuroscience program has approached me with
an observation that I cannot address. He is studying the function of
naturally occurring polymorphisms in the 3'UTR of the dopamine
transporter (varying occurrences of a 40 bp repeat, usually 9 or 10
repeats). He created constructs containing 0 -10 repeats, but did not
modify the sequences encoding protein. All constructs were expressed
fine in heterologous cells, and produced varying amounts of
radiolabeled ligand binding for each construct that appears to be a
reflection of the amount of protein made. When he ran Western blots
of these lysates, the different proteins are differentially
glycosylated, as judged by migration on SDS-PAGE. Enzymatic
deglycosylation reduced all of their sizes to that expected of the
dopamine transporter polypeptide core.
Does anyone know of a precedent in which the 3'UTR influences the
degree of glycosylation? The one idea I had was that it was a
reflection of transit time through the secretory pathway, but the
glycosylation patterns (by 1D gels) do not correlate with the amount
of dopamine transporter synthesized by these cells (i.e., the
constructs making the most and least protein are both maximally
glycosylated vs other constructs)
Any ideas would be greatly appreciated.
Best regards,
Barry Shur
--
Barry D. Shur, Ph.D.
Candler Professor and Chairman
Department of Cell Biology
Emory University School of Medicine
615 Michael Street
Atlanta, GA 30322
voice: 404-727-4315
cell: 404-313-5469
fax: 404-727-6256
email: barry at cellbio.emory.edu
