Homie shields the <i>TER94</i> promoter from <i>eve</i> PRE activity.

<p><b>A:</b> map of the <i>eve-TER94</i> transgene. The 3^rd exon of the <i>TER94</i> protein coding region is fused to that of GFP, while the <i>eve</i> coding region is replaced by that of <i>lacZ</i>. Otherwise, the transgene consists of the entire genomic region from −6.4 kb to +11.3 kb relative to the <i>eve</i> TSS, and includes all of the <i>eve</i> enhancers, plus <i>TER94</i> enhancers located within its first two introns. The locations of the major <i>eve</i> PRE (“<i>eve</i> PRE”), 3′ insulator (“Homie”), early embryonic stripe enhancers (numbered), and late embryonic enhancers (labeled) are shown as colored boxes. <b>B:</b> embryonic expression, at the indicated stages, of GFP RNA, driven by the <i>TER94</i> promoter, from the transgene shown in A (top row “intact t'gene”), or the same transgene modified by deletion of either the insulator alone (2^nd row “ΔHomie”), the PRE alone (bottom row “ΔPRE”), or both (3^rd row “ΔHomie ΔPRE”), each inserted at attP landing site 95E5, visualized by whole-mount <i>in situ</i> hybridization. Note that the normal, ubiquitous expression (mimicking <i>TER94</i>) is changed to resemble the <i>eve</i> pattern (shown for comparison at the bottom) by deletion of Homie, while further deletion of the PRE restores <i>TER94</i>-like expression. Deletion of the PRE alone does not noticeably affect the embryonic pattern.