Title

An essential role for the RNA-binding protein Smaug during the Drosophila maternal-to-zygotic transition

UMMS Affiliation

Program in Molecular Medicine

Date

2-24-2009

Document Type

Article

Subjects

Animals; DNA Replication; Drosophila Proteins; Drosophila melanogaster; Female; Gene Expression Regulation, Developmental; Genome, Insect; MicroRNAs; *Mothers; Multigene Family; Oligonucleotide Array Sequence Analysis; RNA-Binding Proteins; Repressor Proteins; Zygote

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Genetic control of embryogenesis switches from the maternal to the zygotic genome during the maternal-to-zygotic transition (MZT), when maternal mRNAs are destroyed, high-level zygotic transcription is initiated, the replication checkpoint is activated and the cell cycle slows. The midblastula transition (MBT) is the first morphological event that requires zygotic gene expression. The Drosophila MBT is marked by blastoderm cellularization and follows 13 cleavage-stage divisions. The RNA-binding protein Smaug is required for cleavage-independent maternal transcript destruction during the Drosophila MZT. Here, we show that smaug mutants also disrupt syncytial blastoderm stage cell-cycle delays, DNA replication checkpoint activation, cellularization, and high-level zygotic expression of protein coding and micro RNA genes. We also show that Smaug protein levels increase through the cleavage divisions and peak when the checkpoint is activated and zygotic transcription initiates, and that transgenic expression of Smaug in an anterior-to-posterior gradient produces a concomitant gradient in the timing of maternal transcript destruction, cleavage cell cycle delays, zygotic gene transcription, cellularization and gastrulation. Smaug accumulation thus coordinates progression through the MZT.

Rights and Permissions

Citation: Development. 2009 Mar;136(6):923-32. Link to article on publisher's site

Related Resources

Link to Article in PubMed

PubMed ID

19234062