PT  - JOURNAL ARTICLE
AU  - Wen Xi Cao
AU  - Sarah Kabelitz
AU  - Meera Gupta
AU  - Eyan Yeung
AU  - Sichun Lin
AU  - Christiane Rammelt
AU  - Christian Ihling
AU  - Filip Pekovic
AU  - Timothy C. H. Low
AU  - Najeeb U. Siddiqui
AU  - Matthew H. K. Cheng
AU  - Stephane Angers
AU  - Craig A. Smibert
AU  - Martin Wühr
AU  - Elmar Wahle
AU  - Howard D. Lipshitz
TI  - Precise temporal regulation of post-transcriptional repressors is required for an orderly <em>Drosophila</em> maternal-to-zygotic transition
AID  - 10.1101/862490
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 862490
4099  - http://biorxiv.org/content/early/2019/12/03/862490.short
4100  - http://biorxiv.org/content/early/2019/12/03/862490.full
AB  - In animal embryos the maternal-to-zygotic transition (MZT) hands developmental control from maternal to zygotic gene products. We show that the maternal proteome represents over half of the protein coding capacity of the Drosophila melanogaster genome and that 2% of this proteome is rapidly degraded during the MZT. Cleared proteins include the post-transcriptional repressors Cup, Trailer hitch (TRAL), Maternal expression at 31B (ME31B), and Smaug (SMG). While the ubiquitin-proteasome system is necessary for clearance of all four repressors, distinct E3 ligase complexes target them: the C-terminal to Lis1 Homology (CTLH) complex targets Cup, TRAL and ME31B for degradation early in the MZT; the Skp/Cullin/F-box-containing (SCF) complex targets SMG at the end of the MZT. Deleting the C-terminal 233 amino acids of SMG makes the protein immune to degradation. We show that artificially persistent SMG downregulates the zygotic re-expression of mRNAs whose maternal contribution is cleared by SMG. Thus, clearance of SMG permits an orderly MZT.