1. Transcriptional Timers Regulating Mitosis in Early Drosophila Embryos
Amir Momen-Roknabadi, Stefano Di Talia, Eric Wieschaus 
Cell Reports 
Volume 16, Issue 11, Pages (September 2016)
DOI: /j.celrep
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2. Cell Reports 2016 16, 2793-2801DOI: (10.1016/j.celrep.2016.08.034)
Copyright © 2016 The Authors Terms and Conditions

3. Figure 1
Btd Acts through the MD2 Enhancer to Regulate the MD2 Temporal Pattern
(A and B) Cropped confocal images of the head region of an embryo expressing His2Av-RFP in a 1× Btd (A) and 4× Btd (B) background. Cells belonging to MD1 and MD2 are highlighted in red and blue, respectively. The cells undergoing division are marked yellow.
(C) Percentage of cells that have divided inside MD2 and MD1 (inset) as a function of time (minutes). The data were aligned at the time that 50% of MD1 has divided. The start time was normalized using WT data, around 74 min at 23°C.
Cell Reports  , DOI: ( /j.celrep )
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4. Figure 2 Overview of the Screen (A) General scheme of the screen.
(B) Schematic of an embryo in cycle 14. The cells undergoing mitosis are marked with an antibody against phospho-H3 (Ser10).
(C) Cropped still images of embryos undergoing mitosis in MD1 and MD2. The brightness of the images is increased for enhanced presentation.
(D) Number of cells dividing in MD1 or MD2 versus PMG length/embryo length can be used to calculate a linear fit. Deviation of the linear fit in WT versus deficiency embryos can be due to a shift in timing of MDs (intercept) or change in the mitosis rate (slope).
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5. Figure 3
Heterozygosity of 13 Deficiency Lines Affects the Temporal Pattern of MD1 or MD2
(A) Relative progression of mitosis in MD1 (left) and MD2 (right) versus PMG length/embryo length.
(B) The relative progression of mitosis in MD1 versus MD2 in mutants heterozygous for patterning genes in an identified chromosomal region (red lines and “o”) shows the same deviation from the WT (black lines and “.”) as the corresponding deficiency (blue lines and “+”).
See also Figure S1 and Tables S1 and S2.
Cell Reports  , DOI: ( /j.celrep )
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6. Figure 4
Effects of Double-Mutant Heterozygotes on the Temporal Pattern of MD2
(A) The effect of double-mutant heterozygotes on the number of cells dividing in MD2 versus MD1.
(B) Confocal images of embryos expressing Btd ubiquitously and GFP under control of the MD2 enhancer element. The expression of GFP is only limited in the head region under the control of MD1, MD2, and MD5 enh in WT embryos. When Btd is expressed ubiquitously, GFP is expanded to the abdomen. The image brightness is increased.
(C) Activators and repressors work together to set the temporal pattern of cdc25string. In our favored model, robust timing of cdc25string expression is achieved by integrating both the decline in repressors (red) and the increase in activators (blue). Transcription is initiated when the ratio of activators to repressors crosses a specific threshold (dashed line).
See also Figure S2 and Table S3.
Cell Reports  , DOI: ( /j.celrep )
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