Multiple Cdk1 inhibitory kinases regulate the cell cycle during development.
The Wee kinases block entry into mitosis by phosphorylating and inhibiting the activity of the mitotic cyclin-dependent kinase, Cdk1. We have found that the various Xenopus Wee kinases have unique temporal and spatial patterns of expression during development. In addition, we have isolated and characterized a new Wee1-like kinase, Xenopus Wee2. By both in vivo and in vitro tests, Xenopus Wee2 functions as a Wee1-like kinase. The previously isolated Wee1-like kinase, Xenopus Wee1, is expressed only as maternal gene product. In contrast, Xenopus Wee2 is predominantly a zygotic gene product, while the third Wee kinase, Xenopus Myt1, is both a maternal and zygotic gene product. Concurrent with the changing levels of these Cdk inhibitory kinases, the pattern of embryonic cell division becomes asynchronous and spatially restricted in the Xenopus embryo. Interestingly, once zygotic transcription begins, Xenopus Wee2 is expressed in regions of the embryo that are devoid of mitotic cells, such as the involuting mesoderm. In contrast, Xenopus Myt1 is expressed in regions of the embryo that have high levels of proliferation, such as the developing neural tissues. The existence of multiple Wee kinases may help explain how distinct patterns of cell division arise and are regulated during development.
Leise
Walter
W
Department of Biochemistry and Molecular Biology, Cener for Molecular Oncology and Committees on Developmental Biology, Cancer Biology, and Genetics, University of Chicago, Ill 60637, USA.
Mueller
Paul R
PR
D000595:Amino Acid Sequence; D000818:Animals; D016203:CDC2 Protein Kinase / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins; D003001:Cloning, Molecular; D004625:Embryo, Nonmammalian / Q000166:cytology; D005260:Female; D005775:Gastrula / Q000166:cytology; D018507:Gene Expression Regulation, Developmental; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism; D008938:Mitosis; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014981:Xenopus / Q000196:embryology* / Q000235:genetics; D029867:Xenopus Proteins / Q000235:genetics* / Q000378:metabolism*
D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D029867:Xenopus Proteins; C095970:MYT1 kinase, Xenopus; C530005:WEE1 protein, Xenopus; C466028:Wee2 protein, Xenopus; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase