| dc.description.abstract | In most organisms, early embryonic development is regulated by mRNA and protein provided by the mother. No transcription occurs until the maternal-to-zygotic transition（MZT）. During MZT, there are two events: the degradation of maternal components, and the activation of zygotic genome（ZGA）. The first discovered master regulator which initiates ZGA is Zelda（Zld）in Drosophila melanogaster （Liang et al., 2008）. Zld activates early zygotic genome through the TAG sites （CAGGTAG and related motifs）enriched in the upstream of early genes（ten Bosch et al., 2006）. In the previous studies, chromatin immunoprecipitationsequencing（ChIP-seq）with anti-Zld antibody detected more than ten thousand of Zld-bound regions in early embryos（Harrison et al. al., 2011）. However, just a thousand of zygotic genes or more were Zld-dependent, suggesting only partial bound regions are functional. How to map these enhancers and determine their activities requires more studies. A new technology, self-trancribing active regulatory region sequencing （STARR-seq）, could simultaneously map and quantify enhancer activities in the whole genome scale. Arnold et al. performed STARR-seq analysis in Drosophila S2 cells（s2-STARR-seq）and the feasibility of this system was validated by DHS-seq, FAIRE-seq, and ChIP-seq（Arnold et al., 2013）. Utilizing this approach, we aimed to identify genome-wide functional Zld-dependent enhancers in S2 cells. (1) Since iv Zld is not expressed in S2 cells, we first ectopically expressed Zld in S2 cells by Bacto-Bac system. (2) We tested two Zld-responsive enhancers of zen（4zld, VRE）and two Act5C enhancers（Act5c2, Act5c3）as positive controls to test the possibility to perform STARR-seq in S2 cells ectopically expressing Zld [S2（+Zld）-STARRseq]. We also tested three STARR-seq-vectors containing different core promoters, including development-related promoters, Fly and pnr, and a housekeeping gene promoter, RpS12. (3) The strength of enhancer-driven GFP in the presence or absence of Zld in S2 cells was tested by RT-qPCR. Our results showed that with the help of Zld, the activity of 4Zld and VRE had significant increased, indicating that Zld-dependent enhancers are able to drive GFP expression with the presence of Zld. Also, developmental enhancers showed preference for developmental core promoters. Experiment timeline and conditions were suggested. This platform will be further used to perform whole-genome S2 （Zld）-STARR-seq analysis, for identifying functional Zld-dependent enhancers, in the hope to investigate their features corresponding to activities | en_US |