Characteristic expression of Hck in human B-cell precursors.
OBJECTIVE
To identify molecules involved in signaling for early B-cell development, we investigated the expression of signal transduction-related proteins in B-cell progenitors.


METHODS
[corrected] Normal as well as leukemic B-cell progenitors were examined by immunoblotting and immunofluorescence study.


RESULTS
[corrected] In a survey of the expression of a broad range of signal transduction molecules, the Src-family protein tyrosine kinases were found to be differentially expressed in early B-cell differentiation. [corrected] Analysis of freshly prepared precursor-B acute lymphoblastic leukemia cells and B-lineage cell lines showed Hck and Lyn are major Src-family protein tyrosine kinases expressed in this type of leukemic blasts. [corrected] However, heterogeneity of Hck and Lyn expression was found in these cells, and precursor-B acute lymphoblastic leukemia cells subsequently were classified according to the expression pattern of Hck and Lyn as Hck/Lyn dual-negative, Hck-predominant, Hck/Lyn dual-positive, and Lyn-predominant. Further studies on normal B-lineage cells indicated that the Src-family protein tyrosine kinases are expressed sequentially in a differentiation-dependent fashion during B-cell ontogeny and that the predominant expression of Hck is a common feature in B-cell progenitors, whereas Lyn expression is more significant in mature B cells.


CONCLUSIONS
Although the biologic significance remains unknown, sequential expression of Src-family protein tyrosine kinases should play a role in regulation of early B-cell differentiation.
Taguchi
T
T
Department of Pathology, National Children's Medical Research Center, Tokyo, Japan.
Kiyokawa
N
N
Sato
N
N
Saito
M
M
Fujimoto
J
J
D015703:Antigens, CD / Q000096:biosynthesis; D000954:Antigens, Surface / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000166:cytology / Q000201:enzymology* / Q000276:immunology; D002051:Burkitt Lymphoma / Q000201:enzymology* / Q000276:immunology / Q000473:pathology; D002454:Cell Differentiation / Q000276:immunology; D002460:Cell Line; D019070:Cell Lineage; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000201:enzymology* / Q000276:immunology; D006801:Humans; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D051572:Proto-Oncogene Proteins c-hck; D015398:Signal Transduction / Q000276:immunology; D013997:Time Factors; D019061:src-Family Kinases / Q000096:biosynthesis / Q000378:metabolism
D015703:Antigens, CD; D000954:Antigens, Surface; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C496631:HCK protein, human; D051572:Proto-Oncogene Proteins c-hck; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases