|ZFIN ID: ZDB-PUB-021016-7|
Treatment with Myf5-morpholino results in somite patterning and brain formation defects in zebrafish
Chen, Y.-H. and Tsai, H.-J.
|Source:||Differentiation; research in biological diversity 70(8): 447-456 (Journal)|
|Registered Authors:||Chen, Yau-Hung, Tsai, Huai-Jen|
|Keywords:||brain; embryogenesis; fish; morphant; morpholino; myf5; somite|
|PubMed:||12366382 Full text @ Differentiation|
Chen, Y.-H. and Tsai, H.-J. (2002) Treatment with Myf5-morpholino results in somite patterning and brain formation defects in zebrafish. Differentiation; research in biological diversity. 70(8):447-456.
ABSTRACTMyf-5 is a stage-dependent transcription factor associated with somitogenesis. To study its biological functions in zebrafish, we injected the Myf5-morpholinos ZMF-MO (antisense nucleotides 28 to 52) and ZMF-OTHER (antisense nucleotides 3 to 27) into zebrafish embryos to establish a myf-5 gene knockdown. No phenotypic abnormalities were observed following injection with 0.2 ng of ZMF-MO, but defects were displayed in 2 of 118 (1.7%) surviving embryos injected with 1 ng ZMF-MO Morphological defects became more severe with increased dosages: 105 of 270 (38.9%) surviving embryos injected with 4.5 ng of ZMF-MO displayed such abnormalities as the absence of eyes or brains in addition to the following low-dosage defects in 24 hpf embryos: longitudinal yolk sacs, incomplete epiboly coverage, abnormal and suspended tail buds, diffused somite boundaries, and head shrinkage. Similar results were observed in the 4.5 ng ZMF-OTHER injection group. However, when fish were co-injected with 4.5 ng ZMF-MO and 4.5 ng myf-5 mRNA, abnormality rates decreased from 49.6% to 5.5%. Our results show that the brain krox20 gene was down-regulated at rhombomere 3; the pax2. 1 gene was completely down-regulated; myoD was expressed normally; myogenin was substantially down-regulated in whole somites; and desmin was partly inhibited in newly forming somites. Our conclusion is that zebrafish Myf-5 may play important roles in brain formation and in the convergence and extension of shield epiblasts and tail buds during early embryogenesis, in addition to its well-understood role as a muscle regulatory factor in somites.