Threshold response of<i>C15</i>to the Dpp gradient in<i>Drosophila</i>is established by the cumulative effect of Smad and Zen activators and negative cues

Lin, Meng Chi; Park, Jeongsook; Kirov, Nikolai; Rushlow, Christine

doi:10.1242/dev.02689

Cited by 28 publications

(27 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Drosophila, the transcripts and proteins of all three genes are expressed throughout the developing amnioserosa, albeit in different time windows. Extraembryonic C15 expression starts in the blastoderm and continues until after germband retraction (25,26). Extraembryonic pnr expression starts in the blastoderm and fades during the extended germband stage (stage 10) (27).…”

Section: Phenotypic Effects Of Zen Rnai In Megaselia and Episyrphusmentioning

confidence: 99%

Evolutionary origin of the amnioserosa in cyclorrhaphan flies correlates with spatial and temporal expression changes of zen

Rafiqi

Lemke

Ferguson

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

121

View full text Add to dashboard Cite

Higher cyclorrhaphan flies including Drosophila develop a single extraembryonic epithelium (amnioserosa), which closes the germband dorsally. In most other insects two extraembryonic epithelia, serosa and amnion, line the inner eggshell and the ventral germband, respectively. How the two extraembryonic epithelia evolved into one is unclear. Recent studies have shown that, in the flour beetle Tribolium and in the milkweed bug Oncopeltus, the homeobox gene zerknü llt (zen) controls the fusion of the amnion with the serosa before dorsal closure. To understand the origin of the amnioserosa in evolution, we examined the expression and function of zen in the extraembryonic tissue of lower Cyclorrhapha. We show that Megaselia abdita (Phoridae) and Episyrphus balteatus (Syrphidae) develop a serosa and a dorsal amnion, suggesting that a dorsal amnion preceded the origin of the amnioserosa in evolution. Using Krü ppel (Kr) and pannier (pnr) homologues of Megaselia as markers for serosal and amniotic tissue, respectively, we show that after zen RNAi all extraembryonic tissue becomes indistinguishable from amniotic cells, like in Tribolium but unlike in Drosophila, in which zen controls all aspects of extraembryonic development. Compared with Megaselia and Episyrphus, zen expression in Drosophila is extended to cells that form the amnion in lower Cyclorrhapha and is down-regulated at the developmental stage, when serosa cells in lower Cyclorrhapha begin to expand. These expression differences between species with distinct extraembryonic tissue organizations and the conserved requirement of zen for serosa development suggest that the origin of an amnioserosa-like epithelium was accompanied by expression changes of zen.Megaselia ͉ Episyrphus ͉ Drosophila ͉ EvoDevo ͉ homology

show abstract

Section: Phenotypic Effects Of Zen Rnai In Megaselia and Episyrphusmentioning

confidence: 99%

Evolutionary origin of the amnioserosa in cyclorrhaphan flies correlates with spatial and temporal expression changes of zen

Rafiqi

Lemke

Ferguson

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

121

View full text Add to dashboard Cite

show abstract

“…S7 in the supplementary material), although it was weaker than the previously published intronic C15 enhancer (Fig. 4A, fragment 3) (Lin et al, 2006).…”

Section: Fig 3 Overexpression Of Ladybird and C15 Represses Evementioning

confidence: 51%

“…S3 in the supplementary material, Apis). In Drosophila, C15 is expressed in the dorsal ectoderm (Lin et al, 2006) and in the leg discs, where it works with aristaless to pattern the distal tip of the leg (Campbell, 2005). Drosophila C15 is additionally expressed in a subset of dorsal mesodermal cells outside the cardiac field (M. Frasch, personal communication).…”

Section: Apismentioning

confidence: 99%

“…In Drosophila, enhancers downstream of the lbl gene (fragment 1) and in the lbl intron (fragment 2) drive a lacZ reporter in the cardiac mesoderm like the lb genes (C,E). A published enhancer in the C15 intron (fragment 3) (Lin et al, 2006) and an additional downstream enhancer (fragment 4) drive expression in the dorsal ectoderm (G and Fig. S7 in the supplementary material).…”

Section: Regulation Of Enhancer-promoter Interactionsmentioning

confidence: 99%

See 1 more Smart Citation

Evolving enhancer-promoter interactions within the tinman complex of the flour beetle,Tribolium castaneum

2009

View full text Add to dashboard Cite

Modifications of cis-regulatory DNAs, particularly enhancers, underlie changes in gene expression during animal evolution. Here, we present evidence for a distinct mechanism of regulatory evolution, whereby a novel pattern of gene expression arises from altered gene targeting of a conserved enhancer. The tinman gene complex (Tin-C) controls the patterning of dorsal mesodermal tissues, including the dorsal vessel or heart in Drosophila. Despite broad conservation of Tin-C gene expression patterns in the flour beetle (Tribolium castaneum), the honeybee (Apis mellifera) and the fruit fly (Drosophila melanogaster), the expression of a key pericardial determinant, ladybird, is absent from the dorsal mesoderm of Tribolium embryos. Evidence is presented that this loss in expression is replaced by expression of C15, the neighboring gene in the complex. This switch in expression from ladybird to C15 appears to arise from an inversion within the tinman complex, which redirects a conserved ladybird 3Ј enhancer to regulate C15. In Drosophila, this enhancer fails to activate C15 expression owing to the activity of an insulator at the intervening ladybird early promoter. By contrast, a chromosomal inversion allows the cardiac enhancer to bypass the ladybird insulator in Tribolium. Given the high frequency of genome rearrangements in insects, it is possible that such enhancer switching might be widely used in the diversification of the arthropods.

show abstract

“…Dpp signaling, which activates the transcription factors Mothers against dpp (Mad), and Zen induce dorsal ectodermal fate (Raftery et al 1995;Rusch and Levine 1997;Lin et al 2006). We therefore analyzed the occupancy of Mad and Zen in gd 7 embryos and found that their occupancy at both active DEEs and uninduced MEs was also significantly higher than at the closed control regions (Fig.…”

Section: Resultsmentioning

confidence: 97%

Drosophilapoised enhancers are generated during tissue patterning with the help of repression

Koenecke

Johnston

et al. 2016

Preprint

View full text Add to dashboard Cite

Histone modifications are frequently used as markers for enhancer states, but how to interpret enhancer states in the context of embryonic development is not clear. The poised enhancer signature, involving H3K4me1 and low levels of H3K27ac, has been reported to mark inactive enhancers that are poised for future activation. However, future activation is not always observed, and alternative reasons for the widespread occurrence of this enhancer signature have not been investigated. By analyzing enhancers during dorsal-ventral (DV) axis formation in the Drosophila embryo, we find that the poised enhancer signature is specifically generated during patterning in the tissue where the enhancers are not induced, including at enhancers that are known to be repressed by a transcriptional repressor. These results suggest that, rather than serving exclusively as an intermediate step before future activation, the poised enhancer state may be a mark for spatial regulation during tissue patterning. We discuss the possibility that the poised enhancer state is more generally the result of repression by transcriptional repressors.

show abstract

Threshold response ofC15to the Dpp gradient inDrosophilais established by the cumulative effect of Smad and Zen activators and negative cues

Cited by 28 publications

References 42 publications

Evolutionary origin of the amnioserosa in cyclorrhaphan flies correlates with spatial and temporal expression changes of zen

Evolutionary origin of the amnioserosa in cyclorrhaphan flies correlates with spatial and temporal expression changes of zen

Evolving enhancer-promoter interactions within the tinman complex of the flour beetle,Tribolium castaneum

Drosophilapoised enhancers are generated during tissue patterning with the help of repression

Contact Info

Product

Resources

About