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Loyola University Chicago

Department of Biology

Sonja Dabizljevic Thesis Defense: Project Description

Title: Investigating the transcriptional regulation of col2ala in zebrafish



Cartilage is an important tissue in vertebrates beginning in the early embryo where it lays down the scaffolding for the skeleton, and continuing through adulthood where it makes up joints and intervertebral disks.  The major component of cartilage is a filamentous protein known as Collagen type II, alpha 1 (Col2al).  Mutations in col2al in humans can lead to multiple congenital disorders and the early onset of joint and retinal deterioration.  Our laboratory is interested in understanding the conserved transcriptional regulation of this critical structural gene utilizing the zebrafish, Danio rerio.  Previously, we identified a 310 bp regulatory region (R2) 1.7 kb upstream of the transcriptional start site that is critical for cartilage, ear, and notochord expression of the col2ala gene in zebrafish.  Utilizing transgenic zebrafish EGFP reporter analysis, we have narrowed the R2 region down to 120 bp that can still reproduce the full col2ala  mRNA expression seen by in situ hybridization. By reducing the R2 element to 60 bp we can specify cartilage and ear expression, while eliminating notochord expression.  By employing comparative genomic analysis we identified three highly conserved putative transcription factor binding sites for the transcription factor families of Ets, Runx, and Sox. Generation of targeted deletions of these transcription factor binding sites in our transgenic reporter results in loss of EGFP reporter activity, suggesting their necessity for normal col2ala activity.





I would like to thank my thesis advisor, Dr. Rodney M. Dale, for his mentorship during my graduate studies.  His passion for research is contagious and his guidance has been instrumental in my advancement as a scientist.  I am especially grateful for his continuous support during my continued academic endeavors.  Thank you to my fellow Dale lab members who have been valuable assests to have in the laboratory, especially Peter Lyson, Daniel Brissette, and Stephanie Erhard.  I am also very grateful to the members of my committee, Dr. Bryan F. Pickett and Dr. Catherine Putonti, for their support and advice during the completion of my project.





Sonja Dabizljevic of Chicago, Illinois, graduated from Loyola University Chicago in 2009 with a Bachelor of Science degree in Biology.  After working at Dow Chemical as a laboratory technician for almost three years, she returned to the Master of Science program at Loyola University Chicago in 2012 where she joined the lab of Dr. Rodney M. Dale.



Committee Members

Dr. Rodney M. Dale

Dr. Bryan F. Pickett

Dr. Catherine Putonti





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