In vitro development of mouse embryonic stem cells lacking JNK/stress-activated protein kinase-associated protein 1 (JSAP1) scaffold protein revealed its requirement during early embryonic neurogenesis.
The Jsap1 gene encodes a scaffold protein for c-Jun N-terminal kinase cascades. We established c-Jun N-terminal kinase (JNK)/stress-activated protein kinase-associated protein 1 (JSAP1)-null mouse embryonic stem cell lines by homologous recombination. The JSAP1-null embryonic stem cells were viable, however, exhibited hyperplasia of the ectoderm during embryoid body formation, and spontaneously differentiated into neurons more efficiently than did wild type. The expression of components of c-Jun N-terminal kinase cascades and a subset of marker mRNAs during early embryogenesis was altered in the JSAP1-null mutants. Retinoic acid dramatically increased the expression of JSAP1 and JNK3, which were co-precipitated with anti-JNK3 in the neuroectoderm of wild type but not JSAP1-null embryoid bodies. In the neurons differentiated from the wild type embryoid bodies, JSAP1 was localized in the soma, neurites, and growth cone-like structure of the neurites, and neurite outgrowth from the JSAP1-null embryoid bodies was apparently less efficient than from wild type. JSAP1 and c-Jun N-terminal kinase 3 were coexpressed in the embryonic ectoderm of E7.5 mouse embryo, whereas Wnt1 and Pax2 were coexpressed with JSAP1 at the midbrain-hindbrain junction in E12.5 mouse embryo, thus suggesting that JSAP1 is required for early embryonic neurogenesis.
Xu
Ping
P
Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University and CREST, Japan Science and Technology Corp., Fukuoka 812-8582, Japan.
Yoshioka
Katsuji
K
Yoshimura
Daisuke
D
Tominaga
Yohei
Y
Nishioka
Tomoko
T
Ito
Michihiko
M
Nakabeppu
Yusaku
Y
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology*; D002454:Cell Differentiation; D002460:Cell Line; D002470:Cell Survival; D004475:Ectoderm / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology*; D015151:Immunoblotting; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D048057:Mitogen-Activated Protein Kinase 10; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008957:Models, Genetic; D009419:Nerve Tissue Proteins; D009474:Neurons / Q000378:metabolism; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011995:Recombination, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology*; D013997:Time Factors; D014212:Tretinoin / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C403619:Mapk8ip3 protein, mouse; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D014212:Tretinoin; D048057:Mitogen-Activated Protein Kinase 10; D011505:Protein-Tyrosine Kinases; D020928:Mitogen-Activated Protein Kinases