Generation and timing of graded responses to morphogen gradients.
| Autor: | Carmon S; Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel., Jonas F; Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel., Barkai N; Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel., Schejter ED; Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel., Shilo BZ; Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel. |
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| Jazyk: | angličtina |
| Zdroj: | Development (Cambridge, England) [Development] 2021 Dec 15; Vol. 148 (24). Date of Electronic Publication: 2021 Dec 17. |
| DOI: | 10.1242/dev.199991 |
| Abstrakt: | Morphogen gradients are known to subdivide a naive cell field into distinct zones of gene expression. Here, we examine whether morphogens can also induce a graded response within such domains. To this end, we explore the role of the Dorsal protein nuclear gradient along the dorsoventral axis in defining the graded pattern of actomyosin constriction that initiates gastrulation in early Drosophila embryos. Two complementary mechanisms for graded accumulation of mRNAs of crucial zygotic Dorsal target genes were identified. First, activation of target-gene expression expands over time from the ventral-most region of high nuclear Dorsal to lateral regions, where the levels are lower, as a result of a Dorsal-dependent activation probability of transcription sites. Thus, sites that are activated earlier will exhibit more mRNA accumulation. Second, once the sites are activated, the rate of RNA Polymerase II loading is also dependent on Dorsal levels. Morphological restrictions require that translation of the graded mRNA be delayed until completion of embryonic cell formation. Such timing is achieved by large introns, which provide a delay in production of the mature mRNAs. Spatio-temporal regulation of key zygotic genes therefore shapes the pattern of gastrulation. Competing Interests: Competing interests The authors declare no competing or financial interests. (© 2021. Published by The Company of Biologists Ltd.) |
| Databáze: | MEDLINE |
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