Representative third instar larvae used in phenotypic characterizations.

<p><b>A</b>: 63–66 hours after hatching (forager) larvae. The two animals on the left are <i>seq^9.17/+; trio^s036810/trio^M89</i>. The two animals on the right are <i>+/+; trio^s036810/trio^M89</i>. Anterior is up. A millimeter ruler is along the left for scale. <b>B</b>: 90–93 hours after hatching (wanderer) larvae. The two animals on the left are <i>seq^9.17/+; trio^s036810/trio^M89</i>. The smaller animal is representative of 15% of this population. The two animals on the right are <i>+/+; trio^s036810/trio^M89</i>. Anterior is up. A millimeter ruler is along the left for scale.</p

Characterizing the lethal phase of the <i>seq^9.17</i> dominant enhancement.

a<p>Determined by mAb BP102 staining</p>b<p>n = 5 trials with at least 150 animals scored in each trial</p>c<p><i>+/+; trio^s036810/trio^M89</i></p>d<p><i>seq^9.17/+; trio^s036810/trio^M89</i></p><p>***p<0.0001 determined by x²</p

An Allele of <i>Sequoia</i> Dominantly Enhances a <i>Trio</i> Mutant Phenotype to Influence Drosophila Larval Behavior

<div><p>The transition of <i>Drosophila</i> third instar larvae from feeding, photo-phobic foragers to non-feeding, photo-neutral wanderers is a classic behavioral switch that precedes pupariation. The neuronal network responsible for this behavior has recently begun to be defined. Previous genetic analyses have identified signaling components for food and light sensory inputs and neuropeptide hormonal outputs as being critical for the forager to wanderer transition. Trio is a Rho-Guanine Nucleotide Exchange Factor integrated into a variety of signaling networks including those governing axon pathfinding in early development. Sequoia is a pan-neuronally expressed zinc-finger transcription factor that governs dendrite and axon outgrowth. Using pre-pupal lethality as an endpoint, we have screened for dominant second-site enhancers of a weakly lethal <i>trio</i> mutant background. In these screens, an allele of <i>sequoia</i> has been identified. While these mutants have no obvious disruption of embryonic central nervous system architecture and survive to third instar larvae similar to controls, they retain forager behavior and thus fail to pupariate at high frequency.</p></div

Schematic structures of wild type Sequoia and Sequoia^9.17.

<p>Sequoia⁺ is 882 residues long and contains two C2H2 zinc fingers (D375 to K476) shown as dark vertical lines. The 23 base pair deletion in <i>seq^9.17</i> causes a frameshift after Q561, resulting in 260 unique residues (striped box). Sequoia^9.17 retains the two CH2H2 zinc fingers.</p

Characterizing the <i>seq^9.17</i> dominant enhancement in 90–93 hours after hatching larvae (wanderers).

a<p>+/+; trio^s036810/trio^M89</p>b<p>seq^9.17/+; trio^s036810/trio^M89</p>c<p>heterozygous mutant for trio; inherited the balancer chromosome carrying the dominant Tubby marker</p>***<p>p = 0.0009</p>d,e<p>Means from food dispersal assays not sharing the same letter were significantly different at p<0.001</p

Characterizing the <i>seq^9.17</i> dominant enhancement in 63–66 hours after hatching larvae (foragers).

a<p>+/+; trio^s036810/trio^M89</p>b<p>seq^9.17/+; trio^s036810/trio^M89</p>c<p>heterozygous mutant for trio; inherited the balancer chromosome carrying the dominant Tubby marker</p

Dosage-sensitive modification of the <i>trio</i> mutant phenotype^a.

a<p>n = 5 trials with at least 150 animals scored in each trial</p

BET inhibitors suppress ALDH activity by targeting ALDH1A1 super-enhancer in ovarian cancer

The emergence of tumor cells with certain stem-like characteristics, such as high aldehyde dehydrogenase (ALDH) activity due to ALDH1A1 expression, contributes to chemotherapy resistance and tumor relapse. However, clinically applicable inhibitors of ALDH activity have not been reported. There is evidence to suggest that epigenetic regulation of stem-related genes contributes to chemotherapy efficacy. Here, we show that bromodomain and extraterminal (BET) inhibitors suppress ALDH activity by abrogating BRD4-mediated ALDH1A1 expression through a super-enhancer element and its associated enhancer RNA. The clinically applicable small-molecule BET inhibitor JQ1 suppressed the outgrowth of cisplatin-treated ovarian cancer cells both in vitro and in vivo. Combination of JQ1 and cisplatin improved the survival of ovarian cancer-bearing mice in an orthotopic model. These phenotypes correlate with inhibition of ALDH1A1 expression through a super-enhancer element and other stem-related genes in promoter regions bound by BRD4. Thus, targeting the BET protein BRD4 using clinically applicable small-molecule inhibitors, such as JQ1, is a promising strategy for targeting ALDH activity in epithelial ovarian cancer