***** seminarMLから情報転載 *****


第5回生命医科学科講演会
演題: GLYCOME ANALYSIS DURING DIFFERENTIATION OF HUMAN
EMBRYONIC STEM CELLS
演者: John Yu 教授 ( Director&s_comma; Genomics Research Center and Institute of Cellular and Organismic Biology&s_comma; Academia Sinica&s_comma; Taipei&s_comma; Taiwan )
日時:2009年5月14日(木)18:00~
会場:早稲田大学先端生命医科学センター (TWins) 3階セミナールーム3
アクセス:http://www.waseda.jp/advmed/access/index.html
参加費:無料、事前登録不要

概要: We investigated expression of glycans in human ES and
their differentiated derivatives by MALDI-MS profiling and MALDI-CID
MS/MS sequencing. In addition to SSEA-3 and SSEA-4&s_comma; we had
demonstrated the presence of new entities of glycosphingolipids (GSLs)
in human ES cells: Gb4&s_comma; Globo H&s_comma; and disialo-Gal- globoside. We also
found that during ES differentiation&s_comma; core structures of GSLs switched
from globo- and lacto- series (Gala1-4Galb1-4Glcb1-1’Cer and
GlcNAcb1-3Galb1-4Glcb1-1’Cer&s_comma; respectively) to ganglio-series
(NeuNAca2-3Galb1-4Glcb1-1’Cer)&s_comma; consistent with the observed
changes of expression patterns of GSLs during embryonic development.
In addition&s_comma; these alterations could be accounted for by changes of
expression of key glycosyltransferases in biosynthetic pathways of
GSLs. For example&s_comma; Gb5 synthase and globo-H related FUT1/FUT2 were
suppressed when human ES cells differentiated into EB outgrowth&s_comma;
accounting for the absence of SSEA-3 and Glob H in differentiated
cells. But&s_comma; to account for the presence of SSEA-4 in approximately 49%
of cells after ES differentiation&s_comma; there was 18.2 folds increase in
SIAT4A enzyme. On one hand&s_comma; there is substantial decline in the
expression of enzyme A4GALT (74%) which is responsible for inefficient
conversion of lactosylceramide to Gb3 (globo-series GSLs). At the same
time&s_comma; GM3 synthase&s_comma; GD3 synthase and GM2 synthase increased by 14.2&s_comma;
8.9&s_comma; and 8.4 folds&s_comma; respectively. These changes account for the switch
of core structures of GSLs in favor of ganglio-series upon human ES
cell differentiation. GSLs which are present on the cell surface of
human ES cells are involved in cell adhesion and signal transduction.
We envision that glycan structure determinations will significantly
benefit the studies of the functional roles of stem cell surface
markers.

連絡先:南沢 享(早稲田大学先進理工学部生命医科学科) 
sminamis@waseda.jp



seminarMLに関する情報は「バイオ関係者、皆のホームページ」特選MailingList_Forum欄でアクセスできる。