Sialyltransferase mRNA abundances in B cells are strictly controlled, correlated with cognate lectin binding, and differentially responsive to immune signaling in vitro.
Mouse gene knockout studies have provided unimpeachable evidence of immune-relevant functions for several sialyltransferase enzymes including ST6Gal I, ST3Gal I, and ST3Gal IV. Such studies cannot, however, identify cellular mechanisms for regulating such activities. In this article we provide evidence that murine B lymphocytes respond to specific immune signals in vitro with tightly regulated changes in the sialic acid composition of the cell surface glycocalyx. These changes are both quantitative and qualitative in nature and are apparently regulated at both the transcriptional and posttranscriptional levels. We used lectin binding and flow cytometry combined with relative real-time PCR to show that MAH and PNA binding are tightly correlated with the abundance of ST3Gal IV and ST3Gal I mRNA, respectively, under several different conditions of B cell stimulation. Finally, we show that although SNA binding and the expression of ST6Gal I coding sequence are not tightly correlated, there is a clear differential control of 5'UTR exon usage in response to different immune signals.
Faculty of Biological Science and The Mervin Bovaird Center for Studies in Molecular Biology and Biotechnology, 600 S. College Ave., University of Tulsa, Tulsa, OK 74104, USA.
Julie H
JH
Marino
Matt
M
Hoffman
Megan
M
Meyer
Kenton S
KS
Miller
D000818:Animals; D010367:Arachis / Q000737:chemistry; D001402:B-Lymphocytes / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D029901:Maackia / Q000737:chemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D037121:Plant Lectins / Q000276:immunology* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D027924:Sambucus nigra / Q000737:chemistry; D012799:Sialyltransferases / Q000235:genetics* / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology*; D013154:Spleen / Q000166:cytology
D037121:Plant Lectins; D012333:RNA, Messenger; D012799:Sialyltransferases