Unmasking activation of the zygotic genome using chromosomal deletions in the Drosophila embryo.
During the maternal-to-zygotic transition, a developing embryo integrates post-transcriptional regulation of maternal mRNAs with transcriptional activation of its own genome. By combining chromosomal ablation in Drosophila with microarray analysis, we characterized the basis of this integration. We show that the expression profile for at least one third of zygotically active genes is coupled to the concomitant degradation of the corresponding maternal mRNAs. The embryo uses transcription and degradation to generate localized patterns of expression, and zygotic transcription to degrade distinct classes of maternal transcripts. Although degradation does not appear to involve a simple regulatory code, the activation of the zygotic genome starts from intronless genes sharing a common cis-element. This cis-element interacts with a single protein, the Bicoid stability factor, and acts as a potent enhancer capable of timing the activity of an exogenous transactivator. We propose that this regulatory mode links morphogen gradients with temporal regulation during the maternal-to-zygotic transition.
De Renzis
Stefano
S
Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, New Jersey, United States of America. stefanod@Princeton.edu
Elemento
Olivier
O
Tavazoie
Saeed
S
Wieschaus
Eric F
EF
D000818:Animals; D001483:Base Sequence; D002872:Chromosome Deletion; D015536:Down-Regulation; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000502:physiology*; D015533:Transcriptional Activation / Q000502:physiology; D015053:Zygote / Q000502:physiology
D029721:Drosophila Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C523786:bicoid stability factor, Drosophila