Developmental expression of EphB6 in the thymus: lessons from EphB6 knockout mice.
A member of the largest family of receptor protein kinases, EphB6, lacks its intrinsic kinase activity, but it is expressed in normal human tissues. To investigate the physiological function of EphB6, we generated EphB6 deficient mice. EphB6(-/-) mice developed normally, revealed no abnormality in general appearance, and were fertile. Although a developmental increase of EphB6 in the fetal thymus was confirmed, T-cell development in various lymphoid organs of EphB6(-/-) mice was comparable to those of EphB6(+/+). Even in fetal thymus organ cultures, any developmental differences of EphB6(-/-) and EphB6(+/+) thymocytes were undetectable. The different binding characteristics to ephrin-Fc proteins between EphB6(-/-) and EphB6(+/+) thymocytes demonstrated that ephrin-B2 is the unique ligand for EphB6 among eight known ephrins. While EphB6 was a dominant receptor that binds to ephrin-B2 in adult thymocytes, fetal ones also expressed another EphB that binds to ephrin-B2. Overlapping expression of the EphB subfamily in the fetal thymus might compensate for the loss of EphB6 during the thymic development.
Shimoyama
Manabu
M
Division of Hematology/Oncology, Department of Medicine, Kobe University School of Medicine, Chuo-ku, Kobe, Hyogo 650-0017, Japan.
Matsuoka
Hiroshi
H
Nagata
Aki
A
Iwata
Nobuko
N
Tamekane
Akira
A
Okamura
Atsuo
A
Gomyo
Hiroshi
H
Ito
Mitsuhiro
M
Jishage
Kou-ichi
K
Kamada
Nobuo
N
Suzuki
Hiroshi
H
Tetsuo Noda
Tetsuo
T
Matsui
Toshimitsu
T
D000818:Animals; D001772:Blood Cell Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002454:Cell Differentiation; D018390:Gene Targeting; D051379:Mice; D018345:Mice, Knockout; D009924:Organ Culture Techniques; D012333:RNA, Messenger / Q000032:analysis; D036261:Receptor, EphB6 / Q000235:genetics* / Q000378:metabolism*; D036081:Receptors, Eph Family / Q000378:metabolism; D013154:Spleen / Q000276:immunology; D013950:Thymus Gland / Q000196:embryology* / Q000276:immunology
D012333:RNA, Messenger; D036261:Receptor, EphB6; D036081:Receptors, Eph Family