The Influence of Lozenge on Protein Tyrosine Phosphatase 69D Expression
Bayer School of Natural and Environmental Sciences
John A. Pollock
gene expression, lozenge, lz, protein tyrosine phosphatase, ptp69D
Lozenge is a transcription factor in the Runx protein family, which also includes human Acute Myeloid Leukemia (AML-1), Runt, and Core Binding Factor Alpha Subunit 2-like transcription factor. Among other functions in various tissues, Lozenge is involved in Drosophila melanogaster eye development. In addition to suppressing cell death in the developing eye (Siddall et al., 2003), Lozenge contributes to the completion of development of ommatidia by influencing the differentiation of photoreceptor cells R1, R6, and R7 (Crew et al., 1997); (Flores et al., 1998). The expression of the lozenge in the eye is regulated by a mechanism linked to the progression of the morphogenetic furrow (Crew et al., 1997); (Yan et al., 2003). Previous data has also suggested that a reduction in lozenge mRNA expression affects downstream genes involved in photoreceptor differentiation including Prospero, Runt, Bar, and Sevenup (Crew et al., 1997); (Behan et al., 2002).
My results of quantitative reverse-transcriptase PCR and quantitative immunohistochemistry show a reduction in PTP69D mRNA expression and protein expression, in the lozenge mutant Lz77a7 compared to wildtype expression. Using computational analysis of the promoter and enhancer regions of ptp69D, I have also found multiple binding sites for Lozenge and its binding partner Pointed. Thus, my thesis provides support for two hypotheses that Lozenge activates expression of ptp69D in photoreceptor cells R1 and R6 or in R7 only.
Nightingale, B. (2006). The Influence of Lozenge on Protein Tyrosine Phosphatase 69D Expression (Master's thesis, Duquesne University). Retrieved from https://dsc.duq.edu/etd/1672