Next Article in Journal
Regulation of Actin Dynamics in the C. elegans Somatic Gonad
Next Article in Special Issue
Hedgehog Signaling and Embryonic Craniofacial Disorders
Previous Article in Journal
The Forgotten Skeletogenic Condensations: A Comparison of Early Skeletal Development Amongst Vertebrates
Previous Article in Special Issue
Sonic Hedgehog Is a Member of the Hh/DD-Peptidase Family That Spans the Eukaryotic and Bacterial Domains of Life
Open AccessArticle

Distinct Activities of Gli1 and Gli2 in the Absence of Ift88 and the Primary Cilia

by Yuan Wang 1,2,†, Huiqing Zeng 1,† and Aimin Liu 1,*
1
Department of Biology, Eberly College of Sciences, Center for Cellular Dynamics, Huck Institute of Life Science, The Penn State University, University Park, PA 16802, USA
2
Department of Occupational Health, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang 110122, China
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
J. Dev. Biol. 2019, 7(1), 5; https://doi.org/10.3390/jdb7010005
Received: 2 November 2018 / Revised: 13 February 2019 / Accepted: 16 February 2019 / Published: 19 February 2019
(This article belongs to the Collection Hedgehog Signaling in Embryogenesis)
The primary cilia play essential roles in Hh-dependent Gli2 activation and Gli3 proteolytic processing in mammals. However, the roles of the cilia in Gli1 activation remain unresolved due to the loss of Gli1 transcription in cilia mutant embryos, and the inability to address this question by overexpression in cultured cells. Here, we address the roles of the cilia in Gli1 activation by expressing Gli1 from the Gli2 locus in mouse embryos. We find that the maximal activation of Gli1 depends on the cilia, but partial activation of Gli1 by Smo-mediated Hh signaling exists in the absence of the cilia. Combined with reduced Gli3 repressors, this partial activation of Gli1 leads to dorsal expansion of V3 interneuron and motor neuron domains in the absence of the cilia. Moreover, expressing Gli1 from the Gli2 locus in the presence of reduced Sufu has no recognizable impact on neural tube patterning, suggesting an imbalance between the dosages of Gli and Sufu does not explain the extra Gli1 activity. Finally, a non-ciliary Gli2 variant present at a higher level than Gli1 when expressed from the Gli2 locus fails to activate Hh pathway ectopically in the absence of the cilia, suggesting that increased protein level is unlikely the major factor underlying the ectopic activation of Hh signaling by Gli1 in the absence of the cilia. View Full-Text
Keywords: Hh signaling; Shh; neural tube; patterning; intraflagellar transport; Gli3; Sufu; Smo; mouse Hh signaling; Shh; neural tube; patterning; intraflagellar transport; Gli3; Sufu; Smo; mouse
Show Figures

Figure 1

MDPI and ACS Style

Wang, Y.; Zeng, H.; Liu, A. Distinct Activities of Gli1 and Gli2 in the Absence of Ift88 and the Primary Cilia. J. Dev. Biol. 2019, 7, 5.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop