SpKrl: a direct target of beta-catenin regulation required for endoderm differentiation in sea urchin embryos.
Localization of nuclear beta-catenin initiates specification of vegetal fates in sea urchin embryos. We have identified SpKrl, a gene that is activated upon nuclear entry of beta-catenin. SpKrl is upregulated when nuclear beta-catenin activity is increased with LiCl and downregulated in embryos injected with molecules that inhibit beta-catenin nuclear function. LiCl-mediated SpKrl activation is independent of protein synthesis, indicating that SpKrl is a direct target of beat-catenin and TCF. Embryos in which SpKrl translation is inhibited with morpholino antisense oligonucleotides lack endoderm. Conversely, SpKrl mRNA injection rescues some vegetal structures in beta-catenin-deficient embryos. SpKrl negatively regulates expression of the animalizing transcription factor, SpSoxB1. We propose that SpKrl functions in patterning the vegetal domain by suppressing animal regulatory activities.
Howard
E W
EW
Department of Biology, University of Rochester, Rochester, NY 14627, USA.
Newman
L A
LA
Oleksyn
D W
DW
Angerer
R C
RC
Angerer
L M
LM
D000595:Amino Acid Sequence; D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism; D002450:Cell Communication; D002454:Cell Differentiation; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D004475:Ectoderm / Q000166:cytology / Q000378:metabolism; D004707:Endoderm / Q000166:cytology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D017403:In Situ Hybridization; D018021:Lithium Chloride / Q000494:pharmacology; D008954:Models, Biological; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D021381:Protein Transport; D011518:Proto-Oncogene Proteins / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055748:SOXB1 Transcription Factors; D012617:Sea Urchins / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D016335:Zinc Fingers; D051176:beta Catenin
D003598:Cytoskeletal Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D055748:SOXB1 Transcription Factors; C402390:SoxB1 protein, Strongylocentrotus purpuratus; C421384:SpKrl protein, Strongylocentrotus purpuratus; D015534:Trans-Activators; D014157:Transcription Factors; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin; D018021:Lithium Chloride