480B Poster - 06. Regulation of gene expression
Friday April 08, 2:00 PM - 4:00 PM

Authors:
Cody Stevens; Nir Yakoby

Affiliation: Rutgers University Camden

Keywords:
e. enhancers; a. axis specification

Tissue development involves highly coordinated expression of transcription factors controlled by complex cis-regulatory elements (CREs). The posterior end of the follicular epithelium is patterned by Midline (MID), the Drosophila homolog of the mammalian Tbx-20 transcription factor. Here, we identify two CREs that recapitulate the endogenous pattern of mid. It has been genetically shown that mid is negatively regulated by the Iroquois transcription factor mirror and the bone morphogenetic protein signaling pathway, while positively activated by the ETS transcription factor pointed. In this study, we corroborate these trans regulators through cis regulation of mid, highlighting regulatory regions within the CREs. Furthermore, through CRISPR/Cas9 genome editing, we illustrate a redundancy of mid CREs. However, deletion of both CREs resulted in a significant reduction, but not loss of mid, indicating additional CREs are possible. Interestingly, unlike the published trans regulatory connection between MID and a second Tbx-20 homolog H15, we found co-regulation between one mid CRE and H15, whereas deletion of this CRE eliminated H15 transcription. These results suggest that both T-box transcription factors mid and H15 share regulatory capacity that may act as safeguards for determination of posterior fate during egg development.