Dual roles of zygotic and maternal Scribble1 in neural migration and convergent extension movements in zebrafish embryos.
In the developing vertebrate hindbrain, the characteristic trajectory of the facial (nVII) motor nerve is generated by caudal migration of the nVII motor neurons. The nVII motor neurons originate in rhombomere (r) 4, and migrate caudally into r6 to form the facial motor nucleus. In this study, using a transgenic zebrafish line that expresses green fluorescent protein (GFP) in the cranial motor neurons, we isolated two novel mutants, designated landlocked (llk) and off-road (ord), which both show highly specific defects in the caudal migration of the nVII motor neurons. We show that the landlocked locus contains the gene scribble1 (scrb1), and that its zygotic expression is required for migration of the nVII motor neurons mainly in a non cell-autonomous manner. Taking advantage of the viability of the llk mutant embryos, we found that maternal expression of scrb1 is required for convergent extension (CE) movements during gastrulation. Furthermore, we show a genetic interaction between scrb1 and trilobite(tri)/strabismus(stbm) in CE. The dual roles of the scrb1 gene in both neuronal migration and CE provide a novel insight into the underlying mechanisms of cell movement in vertebrate development.
Wada
Hironori
H
Laboratory for Developmental Gene Regulation, Brain Science Institute, The Institute of Physical and Chemical Research (RIKEN Saitama 351-0198, Japan.
Iwasaki
Miki
M
Sato
Tomomi
T
Masai
Ichiro
I
Nishiwaki
Yuko
Y
Tanaka
Hideomi
H
Sato
Atsushi
A
Nojima
Yasuhiro
Y
Okamoto
Hitoshi
H
D000818:Animals; D001483:Base Sequence; D002465:Cell Movement / Q000235:genetics / Q000502:physiology*; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D017931:DNA Primers; D005154:Facial Nerve / Q000196:embryology*; D005775:Gastrula / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009046:Motor Neurons / Q000166:cytology*; D009154:Mutation / Q000235:genetics; D016376:Oligonucleotides, Antisense; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012249:Rhombencephalon / Q000196:embryology; D017422:Sequence Analysis, DNA; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism*
D017931:DNA Primers; D008565:Membrane Proteins; D016376:Oligonucleotides, Antisense; D029961:Zebrafish Proteins; C502707:scrib protein, zebrafish; D049452:Green Fluorescent Proteins