Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2001 Jul 13;276(28):26291-300.
doi: 10.1074/jbc.M011124200. Epub 2001 Apr 23.

Point mutations identified in Lec8 Chinese hamster ovary glycosylation mutants that inactivate both the UDP-galactose and CMP-sialic acid transporters

Affiliations
Free article

Point mutations identified in Lec8 Chinese hamster ovary glycosylation mutants that inactivate both the UDP-galactose and CMP-sialic acid transporters

S Oelmann et al. J Biol Chem. .
Free article

Abstract

Nucleotide-sugar transporters (NSTs) are critical components of glycosylation pathways in eukaryotes. The identification of structural elements that are involved in NST functions provides an important task. Chinese hamster ovary glycosylation mutants defective in nucleotide-sugar transport provide access to inactive transporters that can define such structure/function relationships. In this study, we have cloned the hamster UDP-galactose transporter (UGT) and identified defects in UGT gene transcripts from nine independent Chinese hamster ovary mutants that belong to the Lec8 complementation group. Reverse transcription polymerase chain reaction with primers that span the UGT open reading frame showed that three Lec8 mutants express a full-length open reading frame, while six Lec8 mutants predominantly express truncated UGT gene transcripts. Sequencing identified different single or triplet nucleotide changes in full-length UGT transcripts from three of the mutants. These mutations translate into three different amino acid changes at positions that are highly conserved in all the known mammalian NSTs. Transfection of a cDNA encoding either of the mutations Delta serine 213 or G281D failed to correct the UDP-galactose transport defect in Lec8 transfectants. Most importantly, introducing these same mutations into the homologous region of the murine CMP-sialic acid transporter caused inactivation of this transporter. Thus, identifying point mutations that inactivate UGT in Lec8 mutants resulted in the discovery of amino acids that are critical to the activity of both UGT and CST, the two most divergent mammalian NSTs.

PubMed Disclaimer

Publication types

Associated data

LinkOut - more resources