X-Serrate-1 is involved in primary neurogenesis in Xenopus laevis in a complementary manner with X-Delta-1.
Notch, Delta and Serrate encode transmembrane proteins that function in cell fate specification in the Drosophila melanogaster embryo. Here we report gene expression patterns and functional characterization of a Xenopus Serrate homolog, X-Serrate-1. The isolated cDNA encoded a transmembrane protein with a Delta/Serrate/LAG-2 domain, 16 epidermal growth factor-like repeats and a cysteine-rich region. Expression of X-Serrate-1 was observed ubiquitously from unfertilized egg to tadpole, but an upregulation occurred in the tailbud stage embryo. Adult expression was found in eye, brain, kidney, heart, spleen and ovary. Whole-mount in situ hybridization revealed that the organ-related expression in eye, brain, heart and kidney occurred from an early stage of rudiment formation. Overexpression of X-Serrate-1 led to a reduction of primary neurons, whereas an intracellularly deleted form of X-Serrate-1 increased the number of primary neurons. Although the function of X-Serrate-1 in primary neurogenesis was quite similar to that of X-Delta-1, expression of X-Serrate-1 and X-Delta-1 did not affect each other. Co-injection experiments showed that wild-type X-Serrate-1 and X-Delta-1 suppressed overproduction of primary neurons induced by dominant-negative forms of X-Delta-1 and X-Serrate-1, respectively. These results suggest that X-Serrate-1 regulates the patterning of primary neurons in a complementary manner with X-Delta-1-mediated Notch signaling.
Kiyota
T
T
Developmental Biology, Faculty of Science, Kwansei Gakuin University, 1-1-155 Uegahara, Nishinomiya, Hyogo 662-8501, Japan. tom@kwansei.ac.jp
Jono
H
H
Kuriyama
S
S
Hasegawa
K
K
Miyatani
S
S
Kinoshita
T
T
D000595:Amino Acid Sequence; D000818:Animals; D002135:Calcium-Binding Proteins; D003001:Cloning, Molecular; D029721:Drosophila Proteins; D004475:Ectoderm / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D008024:Ligands; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009420:Nervous System / Q000196:embryology* / Q000378:metabolism; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051880:Receptors, Notch; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D000072099:Serrate-Jagged Proteins; D015398:Signal Transduction; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics; D001616:beta-Galactosidase / Q000378:metabolism
D002135:Calcium-Binding Proteins; D029721:Drosophila Proteins; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D008024:Ligands; D008565:Membrane Proteins; D011506:Proteins; D012333:RNA, Messenger; D051880:Receptors, Notch; C000606278:Ser protein, Drosophila; D000072099:Serrate-Jagged Proteins; D029867:Xenopus Proteins; C064045:delta protein; C000606280:jag1 protein, Xenopus; D001616:beta-Galactosidase