Irizarry J, McGehee J, Kim G, Stein D, Stathopoulos A. Twist-dependent ratchet functioning downstream from Dorsal revealed using a light-inducible degron.
Genes Dev 2020;
34:965-972. [PMID:
32467225 PMCID:
PMC7328519 DOI:
10.1101/gad.338194.120]
[Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 04/24/2020] [Indexed: 11/24/2022]
Abstract
Graded transcription factors are pivotal regulators of embryonic patterning, but whether their role changes over time is unclear. A light-regulated protein degradation system was used to assay temporal dependence of the transcription factor Dorsal in dorsal-ventral axis patterning of Drosophila embryos. Surprisingly, the high-threshold target gene snail only requires Dorsal input early but not late when Dorsal levels peak. Instead, late snail expression can be supported by action of the Twist transcription factor, specifically, through one enhancer, sna.distal This study demonstrates that continuous input is not required for some Dorsal targets and downstream responses, such as twist, function as molecular ratchets.
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