Nuclear Trafficking of Cubitus interruptus in the Transcriptional Regulation of Hedgehog Target Gene Expression

Hedgehog (HH) is an important morphogen involved in pattern formation during Drosophila embryogenesis and disc development. cubitus interruptus (ci) encodes a transcription factor responsible for transducing the hh signal in the nucleus and activating hh target gene expression. Previous studies have shown that CI exists in two forms: a 75 kDa proteolytic repressor form and a 155 kDa activator form. The ratio of these forms, which is regulated positively by hh signaling and negatively by PKA activity, determines the on/off status of hh target gene expression. In this paper, we demonstrate that the exogenous expression of CI that is mutant for four consensus PKA sites [CI(m1-4)], causes ectopic expression of wingless (wg) in vivo and a phenotype consistent with wg overexpression. Expression of CI(m1-4), but not CI(wt), can rescue the hh mutant phenotype and restore wg expression in hh mutant embryos. When PKA activity is suppressed by expressing a dominant negative PKA mutant, the exogenous expression of CI(wt) results in overexpression of wg and lethality in embryogenesis, defects that are similar to those caused by the exogenous expression of CI(m1-4). In addition, we demonstrate that, in cell culture, the mutation of any one of the three serine-containing PKA sites abolishes the proteolytic processing of CI. We also show that PKA directly phosphorylates the four consensus phosphorylation sites in vitro. Taken together, our results suggest that positive hh and negative PKA regulation of wg gene expression converge on the regulation of CI phosphorylation.

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An absolute requirement for Cubitus interruptus in Hedgehog signaling

Development ◽

10.1242/dev.128.5.733 ◽

2001 ◽

Vol 128 (5) ◽

pp. 733-742 ◽

Cited By ~ 4

Author(s):

N. Methot ◽

K. Basler

Keyword(s):

Gene Expression ◽

Signal Transduction ◽

Hedgehog Signaling ◽

Target Gene ◽

Target Genes ◽

Signal Transduction Pathway ◽

Transduction Pathway ◽

Cubitus Interruptus ◽

Target Gene Expression ◽

Hh Signaling

Hedgehog (Hh) proteins play diverse organizing roles in animal development by regulating gene expression in responding cells. Several components of the Hh signal transduction pathway have been identified, yet their precise role in mediating the various outputs of the pathway is still poorly understood. The Gli homolog Cubitus interruptus (Ci) is involved in controlling the transcription of Drosophila Hh target genes and thus represents the most downstream component known in this pathway. We address the question of whether the Hh pathway is distally branched or, in other words, whether the regulation of Ci activity is the sole output of Hh signaling. Putative Ci-independent branches of Hh signaling are explored by analyzing the behavior of cells that lack Ci but have undergone maximal activation of the Hh transduction pathway due to the removal of Patched (Ptc). The analysis of target gene expression and morphogenetic read-outs of Hh in embryonic, larval and adult stages indicates that Ci is absolutely required for all examined aspects of Hh outputs. We interpret this as evidence against the existence of Ci-independent branches in the Hh signal transduction pathway and propose that most cases of apparent Ci/Gli-independent Hh output can be attributed to the derepression of target gene expression in the absence of Ci/Gli repressor function.

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2049-P: The Chd4 Helicase of the Nucleosome Remodeling and Deacetylase Complex Modulates Pdx1 Target Gene Expression In Vitro

Diabetes ◽

10.2337/db20-2049-p ◽

2020 ◽

Vol 69 (Supplement 1) ◽

pp. 2049-P

Author(s):

REBECCA K. DAVIDSON ◽

NOLAN CASEY ◽

JASON SPAETH

Keyword(s):

Gene Expression ◽

Target Gene ◽

Nucleosome Remodeling ◽

Target Gene Expression

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On the way toward regulatable expression systems in acetic acid bacteria: target gene expression and use cases

Applied Microbiology and Biotechnology ◽

10.1007/s00253-021-11269-z ◽

2021 ◽

Author(s):

Philipp Moritz Fricke ◽

Angelika Klemm ◽

Michael Bott ◽

Tino Polen

Keyword(s):

Gene Expression ◽

Acetic Acid ◽

Literature Search ◽

Target Gene ◽

Target Genes ◽

Recombinant Dna ◽

Acetic Acid Bacteria ◽

Homoserine Lactone ◽

Expression Systems ◽

Target Gene Expression

Abstract Acetic acid bacteria (AAB) are valuable biocatalysts for which there is growing interest in understanding their basics including physiology and biochemistry. This is accompanied by growing demands for metabolic engineering of AAB to take advantage of their properties and to improve their biomanufacturing efficiencies. Controlled expression of target genes is key to fundamental and applied microbiological research. In order to get an overview of expression systems and their applications in AAB, we carried out a comprehensive literature search using the Web of Science Core Collection database. The Acetobacteraceae family currently comprises 49 genera. We found overall 6097 publications related to one or more AAB genera since 1973, when the first successful recombinant DNA experiments in Escherichia coli have been published. The use of plasmids in AAB began in 1985 and till today was reported for only nine out of the 49 AAB genera currently described. We found at least five major expression plasmid lineages and a multitude of further expression plasmids, almost all enabling only constitutive target gene expression. Only recently, two regulatable expression systems became available for AAB, an N-acyl homoserine lactone (AHL)-inducible system for Komagataeibacter rhaeticus and an l-arabinose-inducible system for Gluconobacter oxydans. Thus, after 35 years of constitutive target gene expression in AAB, we now have the first regulatable expression systems for AAB in hand and further regulatable expression systems for AAB can be expected. Key points • Literature search revealed developments and usage of expression systems in AAB. • Only recently 2 regulatable plasmid systems became available for only 2 AAB genera. • Further regulatable expression systems for AAB are in sight.

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