Removal of vegetal yolk causes dorsal deficencies and impairs dorsal-inducing ability of the yolk cell in zebrafish.
To examine the nature of cytoplasm determinants for dorsal specification in zebrafish, we have developed a method in which we remove the vegetal yolk hemisphere of early fertilized eggs (vegetal removed embryos). When the vegetal yolk mass was removed at the 1-cell stage, the embryos frequently exhibited typical ventralized phenotypes: no axial structures developed. The frequency of dorsal defects decreased when the operation was performed at later stages. Furthermore, the yolk cell obtained from the vegetal-removed embryos lost the ability to induce goosecoid in normal blastomeres while the normal yolk cell frequently did so in normal and vegetal-removed embryos. These results suggested that the vegetal yolk cell mass contains the dorsal determinants, and that the dorsal-inducing ability of the yolk cell is dependent on the determinants.
D000818:Animals; D001757:Blastomeres / Q000502:physiology; D019521:Body Patterning; D005326:Fetal Proteins / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D051956:Goosecoid Protein; D018398:Homeodomain Proteins / Q000378:metabolism; D017403:In Situ Hybridization; D008954:Models, Biological; D008969:Molecular Sequence Data; D012097:Repressor Proteins; D020825:T-Box Domain Proteins; D013997:Time Factors; D014157:Transcription Factors; D015017:Yolk Sac / Q000502:physiology*; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins; D000098908:Brachyury Protein