Expression of polypeptide GalNAc-transferases in hematopoietic stem/progenitor cells.
The members of the UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase (pp-GalNAc-T) family, which transfer GalNAc to polypeptide serine and threonine residues, initiate mucin-type O-linked glycosylation. There are at least 13 functionally characterized members of this family in humans, but no studies have been reported of pp-GalNAc-T isoforms in hematopoietic cells. We isolated and purified CD34+ hematopoietic cells from adult bone marrow by magnetic cell sorting and induced them to differentiate into megakaryocytic lineage cells using an optimal combination of hematopoietic growth factors in serum-free liquid medium. RT-PCR revealed that CD34+ cells expressed pp-GalNAc-T1, T2, T3, T4, T6, T7, T10, T11 and T14, but not pp-GalNAc-T8, T9, T12 and T13. The megakaryocytic lineage cells showed significant increases in the expression of pp-GalNAc-T3, T8, T9, T10 and T13, but pp-GalNAc-T11 and T14 became undetectable. In summary, many pp-GalNAc-T isoforms were expressed in CD34+ cells but the expression pattern changed during differentiation into megakaryocytes. The expression patterns of pp-GalNAc-Ts may be necessary to ensure proper O-glycosylation of mucin-type proteins expressed in CD34+ and megakaryocytic cells.
Cheng
Lamei
L
Experimental Hematology Laboratory, Xiang Ya Medical College, Central South University, Xiangya Road #86, Box 24, Changsha 410078, China.
Wang
Xianyou
X
Tan
Mengqun
M
Zhou
Xiaoying
X
Wang
Qiru
Q
D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000201:enzymology*; D006801:Humans; D017350:N-Acetylgalactosaminyltransferases / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D000097763:Polypeptide N-acetylgalactosaminyltransferase
D017350:N-Acetylgalactosaminyltransferases; D000097763:Polypeptide N-acetylgalactosaminyltransferase