The sequence specificity of homeodomain-DNA interaction

Desplan, Claude; Theis, James F.; O’Farrell, Patrick H.

doi:10.1016/0092-8674(88)90123-7

Cited by 483 publications

(340 citation statements)

References 65 publications

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“…Although in vitro studies suggested cooperative binding, the major effect was seen between one and two copies. An increase from four to six copies only marginally improved in vitro binding 9 . Perhaps site occupancy in vivo has a different dependence on the number of copies.…”

Section: Enhancer Strengthmentioning

confidence: 89%

“…The homoeodomain-binding site used to demonstrate ftz-dependent activation is also bound by the en protein in vitro 8,9 . Nonetheless, when en producer plasmid was co-transfected with the responder constructs that are inducible by ftz, no activation occurred.…”

Section: Engrailed Represses Ftz Activationmentioning

confidence: 99%

“…Tandem repeats of four copies of each of these altered sequences (LP4, RP4) were compared to four copies of the original consensus (NP4). In vitro studies had shown that the change from NP to LP had no detectable effect on ftz-binding affinity, whereas the NP to RP change caused about a five-fold reduction in affinity 9 . Consistent with the in vitro results, LP4 and NP4 showed about the same ability to confer ftz activation to the −50hsp70 promoter, whereas RP4 had significantly reduced activity (Fig.…”

Section: Enhancer Strengthmentioning

confidence: 99%

“…Many of these genes encode a 60 amino-acid sequence, the homoeodomain, that is highly conserved through evolution [3][4][5] . This domain contains a putative helix-turn-helix motif 6 such as that found in a number of bacterial regulators 7 , and possesses a sequence-specific DNA-binding activity 8,9 . Numerous regulatory interactions occur among homoeodomain-encoding genes during development.…”

Section: Introductionmentioning

confidence: 99%

“…At least where regulatory interactions between homoeodomain proteins are involved, hints at one important consideration have already been obtained. In vitro binding studies have shown that several distinct homoeodomains that have diverged considerably in their amino-acid sequences bind to the same DNA elements (homoeodomain-binding sites), albeit with somewhat different affinities 9,20 . This suggests that homoeodomain proteins with similar binding specificities may function by interacting with a family of related sites.…”

mentioning

confidence: 99%

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Activation and repression of transcription by homoeodomain-containing proteins that bind a common site

Jaynes

O’Farrell

1988

Nature

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223

148

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The product of the fushi tarazu (ftz) gene is shown to be a site-dependent activator of transcription. In vitro-defined binding sites act as ftz-dependent enhancers in cultured cells. Another homoeodomain-containing protein, the engrailed gene product, competes for homoeodomainbinding sites and counteracts ftz activation.GENETIC analysis in Drosophila melanogaster has identified a group of regulatory genes that participate in embryonic pattern formation 1,2 . Many of these genes encode a 60 amino-acid sequence, the homoeodomain, that is highly conserved through evolution [3][4][5] . This domain contains a putative helix-turn-helix motif 6 such as that found in a number of bacterial regulators 7 , and possesses a sequence-specific DNA-binding activity 8,9 . Numerous regulatory interactions occur among homoeodomain-encoding genes during development. For example, a combination of segmentation and homoeotic gene products, many of which contain homoeodomains 1 , specify the developmental fates of cells in striped patterns 10,11 . Furthermore, homoeodomain-containing proteins (homoeodomain proteins) regulate both each other 12 and downstream (`cytodifferentiation' 13 ) genes. Consequently, it has been attractive to think of homoeodomain proteins as direct regulators of transcription. Due to the complexity of cross-regulatory interactions however, mutations altering or eliminating one homoeodomain protein generally change the expression patterns of many other regulators, confounding efforts to distinguish direct from indirect regulation. Additionally, suspected target genes contain large cis-acting control regions that respond, directly or indirectly, to complex combinations of regulators [14][15][16][17] . As a result, identification of target genes directly regulated by homoeodomain proteins has been problematic.Previous studies have documented instances in which homoeodomain proteins control transcription. The enhancer activity of a DNA fragment from the ftz gene, a homoeodomaincontaining member of the pair-rule class of segmentation genes, suggested that the ftz gene product (ftz) activates its own expression in the embryo 18 . In a different approach a Drosophila tissue culture system was used to show that the Ultrabithorax (Ubx) gene product induces expression of its own promoter, and inhibits the Antennapedia (Antp) (P1) promoter (M. Krasnow and D. S. Hogness, personal communication, see ref. 19 for summary). In these cases however, the complexity of the regulatory circuitry and of the responding control regions leaves open the possibility that the homoeodomain proteins produce these transcriptional effects through intermediaries. To circumvent the complexities of natural target genes, we chose to use binding sites identified in vitro to build homoeodomain-responsive promoters. We find that ftz is a potent activator of transcription from these promoters in cultured cells.During sequential subdivision of the Drosophila embryo to produce segmentally repeating patterns, combinations of regulatory gene prod...

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Section: Enhancer Strengthmentioning

confidence: 89%

Section: Engrailed Represses Ftz Activationmentioning

confidence: 99%

Section: Enhancer Strengthmentioning

confidence: 99%