Developmental changes in the expression pattern of the JNK activator kinase MUK/DLK/ZPK and active JNK in the mouse cerebellum.
JNK is one of the key molecules regulating cell differentiation and migration in a variety of cell types, including cerebral cortical neurons. MUK/DLK/ZPK belongs to the MAP kinase-kinase-kinase class of protein kinases for the JNK pathway and is expressed predominantly in neural tissue. We have determined the expression pattern of MUK/DLK/ZPK and active JNK in the cerebellum at different stages of postnatal development. Quantitative analysis by Western blotting has showed that high expression levels of MUK/DLK/ZPK and active JNK are maintained during the postnatal development of the cerebellum, and that these levels decrease in the adult cerebellum. Immunohistochemical staining has revealed, however, that their distribution in the developing cerebellum is considerably different. Although active JNK is highly concentrated in the premigratory zone of the external germinal layer (EGL), high expression of MUK/DLK/ZPK has been observed in the molecular layer and in the premigratory zone. Neither the active JNK nor MUK protein has been detected in the proliferative zone of the EGL. These observations suggest that during the postnatal development of the cerebellum, the MUK-JNK signaling pathway contributes to the regulation of granule cell differentiation and migration; further, the activity of MUK/DLK/ZPK is tightly regulated by posttranslational mechanisms and by its expression level.
Suenaga
Jun
J
Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
Cui
De Feng
DF
Yamamoto
Isao
I
Ohno
Shigeo
S
Hirai
Syu-ichi
S
D000818:Animals; D002531:Cerebellum / Q000196:embryology* / Q000201:enzymology*; D004789:Enzyme Activation; D018507:Gene Expression Regulation, Developmental; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008954:Models, Biological; D009474:Neurons / Q000201:enzymology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism
D017346:Protein Serine-Threonine Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; C090757:mitogen-activated protein kinase kinase kinase 12