期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1998
卷号：95
期号：2
页码：472-477
DOI：10.1073/pnas.95.2.472
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：A cDNA encoding a {beta}-1,4-galactosyltransferase named {beta}-1,4-GalT II was cloned from a cDNA library of the human breast tumor cell line, MRK-nu-1. Initially, a 860-bp PCR fragment was obtained from MRK-nu-1 mRNA by 3'-rapid amplification of cDNA ends by using two nested degenerate oligonucleotide primers based on a highly conserved amino acid sequence found in the catalytic domain of mammalian {beta}-1,4-galactosyltransferases and Lymnaea stagnalis {beta}-1,4-N-acetylglucosaminyltransferase ({beta}-1,4-GlcNAcT), both of which utilize the same sugar acceptor. This subsequently was used as a probe to isolate a 4.7-kb cDNA that contained an ORF of 1,164 bp predicting a polypeptide of 388 aa. Its deduced amino acid sequence shows an identity of 37% with that of the previously characterized human {beta}-1,4-galactosyltransferase (referred to as {beta}-1,4-GalT I) and of 28% with that of L. stagnalis {beta}-1,4-GlcNAcT. Study of the properties of the {beta}-1,4-GalT II fused to protein A expressed as a soluble form in COS-7 cells revealed that it is a genuine {beta}-1,4-GalT but has no lactose synthetase activity in the presence of -lactalbumin. Northern blot analysis of 24 human tissues showed that they all express the {beta}-1,4-GalT II transcript, although the levels varied. These results indicate that human cells contain another {beta}-1,4-GalT.
关键词：3′-rapid amplification of cDNA ends ; PCR ; glycosyltransferase ; tissue distribution
