The effects of endogenous and exogenous retinoids on facial patterning
department or school: Dentistry, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Hui, Jenny Nga Jen
issued: 2009-08-05T20:08:25Z
issued: 2001
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Retinoids have been known to influence cell migration, interaction, and differentiation, but their role in skeletal development is still unclear. We investigated the role of retinoic acid receptor (RAR) signaling in facial patterning in chicken embryos. Beads soaked in RAR pan-antagonist, AGN 193109, and implanted into the right nasal pit of stage 15 to 20 embryos induced mild skeletal abnormalities. In addition, Msx-1, Msx-2, Shh, and Fgf-8, expression were not altered, implying that AGN 193109 was not potent enough to completely inhibit all endogenous retinoid signaling in vivo. We indirectly studied the in vivo effectiveness of AGN 193109 by implanting embryos with both RAR antagonist and exogenous retinoic acid (RA) soaked beads to determine if the RAR antagonist could antagonize the RA induced teratogenic effect. We demonstrated that a low concentration of exogenous RA could result in failure of outgrowth of the prenasal cartilage and premaxilla. Moreover, the RA induced defects could be rescued by the cotreatment of RAR antagonist, suggesting that AGN 193109 was effective in antagonizing retinoid signaling in vivo for 18 hours and could not be dislodged from RARs by exogenous RA. RA treated embryos did not show any changes in Fgf-8 and Shh expression, implying that Fgf-8 and Shh were independent of retinoid signaling. However, ectopic expression of Msx-2 was induced by RA treatment and was not downregulated by the cotreatment of the RAR antagonist. This data indicated for the first time that Msx-2 was regulated by retinoid signaling but was not important for the patterning of the chicken upper beak. Most importantly, we demonstrated that a temporary downregulation of Msx-1 in stage 24 RA treated embryos resulted in failure of outgrowth of the prenasal cartilage and premaxilla, but this downregulation was recovered by the cotreatment of RAR antagonist. Thus, our study revealed that maintenance of Msx-1 between stage 20 and stage 24 was essential for the outgrow…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/11766
extent: 7001245 bytes
format: application/pdf
note: THE EFFECTS OF ENDOGENOUS A N D EXOGENOUS RETINOIDS ON F A C I A L PATTERNING by J E N N Y N G A JEN HUI B.Sc , The University of British Columbia, 1999 A THESIS SUBMITTED IN P A R T I A L FULFJMENT OF REQUIRMENTS FOR THE DEGREE OF M A S T E R OF SCIENCE in THE F A C U L T Y OF G R A D U A T E STUDIES (Department of Oral Health Sciences, Faculty of Dentistry) We accept thisJJiesis as conforming to. the reqiffred standard THE UNIVERSITY OF BRITISH C O L U M B I A SEPTEMBER 2001 © Jenny Nga Jen Hui, 2001 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia Vancouver, Canada Date DE-6 (2/88) Abstract Retinoids have been known to influence cell migration, interaction, and differentiation, but their role in skeletal development is still unclear. We investigated the role of retinoic acid receptor (RAR) signaling in facial patterning in chicken embryos. Beads soaked in R A R pan-antagonist, A G N 193109, and implanted into the right nasal pit of stage 15 to 20 embryos induced mild skeletal abnormalities. In addition, Msx-1, Msx-2, Shh, and Fgf-8, expression were not altered, implying that A G N 193109 was not potent enough to completely inhibit all endogenous retinoid signaling in vivo. We indirectly studied the in vivo effectiveness of A G N 193109 by implanting embryos with both R A R antagonist and exogenous retinoic acid (RA) soaked beads to determine i f the R A R antagonist could antagonize the R A induced teratogenic effect. We demonstrated that a low concentration of…
has type: Thesis/Dissertation
date issued: 2001-11
is shown at: 10.14288/1.0090003
language: eng
degree discipline: Dental Science
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/11766