Characterization of a mutation and an alternative splicing of UDP-galactose transporter in MDCK-RCAr cell line

Autor: Mariusz Olczak, Eduardo Guillen
Rok vydání: 2006
Předmět:
Zdroj: Biochimica et Biophysica Acta (BBA) - Molecular Cell Research. 1763:82-92
ISSN: 0167-4889
DOI: 10.1016/j.bbamcr.2005.12.006
Popis: The UDP-galactose (UDP-Gal) transporter present in the Golgi apparatus is a member of a transporter family comprising hydrophobic proteins with multiple transmembrane domains. Co-immunoprecipitation experiments showed that the full-length UDP-Gal transporter protein forms oligomeric structures in the MDCK cell. A ricin-resistant mutant of the MDCK cell line (MDCK-RCAr) is deficient in galactose linked to macromolecules because of a lower UDP-Gal transport rate into the Golgi apparatus. We cloned this mutated protein and found that it contains a stop codon close to the 5′ terminus of its open reading frame. We also detected a shorter splicing variant of the UDP-Gal transporter which contains a 183-nt in-frame deletion in both the wild-type and the mutant mRNA. We showed that the protein, when overexpressed, is localized in the Golgi apparatus and could partially correct the phenotype of the MDCK-RCAr and CHO-Lec8 mutant cell lines. The level of mRNA of the UDP-Gal transporter is much lower (25–30 copies per cell) than those of the CMP-sialic acid transporter (100 copies per cell), UDP-N-acetylglucosamine transporter (80 copies per cell), and GDP-fucose transporter (65 copies per cell). The transcript level of the shorter splicing variant of the UDP-Gal transporter is extremely rare in wild-type MDCK cells (a few copies per cell), but it is significantly increased in the mutant, RCA-resistant cells.
Databáze: OpenAIRE
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