Marino Julie H, Tan Chibing, Davis Brenda, Han Eun-Soo, Hickey Morgan, Naukam Rebecca, Taylor Ashlee, Miller Kenton S, Van De Wiele C Justin, Teague T Kent
Department of Surgery, University of Oklahoma College of Medicine, Tulsa, OK 74135, USA.
Glycobiology. 2008 Sep;18(9):719-26. doi: 10.1093/glycob/cwn051. Epub 2008 Jun 5.
Thymocyte development is accompanied by sequential changes in cell surface glycosylation. For example, medullary thymocytes have increased levels of alpha2,3-linked sialic acid and a loss of asialo core 1 O-glycans as compared to cortical thymocytes. Some of these changes have been linked to fine tuning of the T cell receptor avidity. We analyzed ST6Gal I transcript abundance and levels of alpha2,6-linked sialic acid across thymocyte subsets. We found that ST6Gal I transcript levels increased following T cell receptor beta-selection suggesting that this sialyltransferase may influence the development of early thymocyte populations. Indeed, low levels of alpha2,6-linked sialic acid were found in the earliest T lineage cells, and then increased in T cell receptor beta-selected cells. To determine whether ST6Gal I influences T cell development, we analyzed ST6Gal I-deficient mice for disruptions in thymocyte populations. We found reduced thymic cellularity in the ST6Gal I-deficient mice starting in the early thymocyte compartments.
胸腺细胞的发育伴随着细胞表面糖基化的一系列变化。例如，与皮质胸腺细胞相比，髓质胸腺细胞中α2,3连接的唾液酸水平增加，而脱唾液酸核心1 O-聚糖减少。其中一些变化与T细胞受体亲和力的微调有关。我们分析了跨胸腺细胞亚群的ST6Gal I转录本丰度和α2,6连接的唾液酸水平。我们发现，在T细胞受体β选择后，ST6Gal I转录本水平增加，这表明这种唾液酸转移酶可能影响早期胸腺细胞群体的发育。事实上，在最早的T系细胞中发现低水平的α2,6连接的唾液酸，然后在T细胞受体β选择的细胞中增加。为了确定ST6Gal I是否影响T细胞发育，我们分析了ST6Gal I缺陷小鼠的胸腺细胞群体是否受到破坏。我们发现，从早期胸腺细胞区室开始，ST6Gal I缺陷小鼠的胸腺细胞数量减少。
