DETERMINING THE NECESSITY OF PAIR-RULE CIS-REGULATORY ELEMENTS IN DROSOPHILA MELANOGASTER

Abstract

In Drosophila, the regulation of pair-rule genes such as eve involves distinct cis-regulatory elements, including stripe-specific and seven-stripe CREs, which operate in a time and space-dependent manner. To investigate the role of these CREs, I used CRISPR/Cas9 to precisely delete the respective CREs. My results demonstrate that the loss of the eve stripe 2 CRE can be compensated by seven-stripe CREs, despite these elements being controlled by different transcription factors at varying developmental stages. It also does not prevent stripe formation, indicating that seven-stripe CREs can independently drive stripe initiation. Deletion of the eve Late element, which drives seven-stripe expression, results in reduced intensity of stripe expression, particularly in stripes 2, 4, and 5, showing that seven-stripe CREs are crucial for maintaining expression through later developmental stages. These findings suggest that stripe-specific and seven-stripe CREs function coordinately to ensure precise pair-rule gene expression, emphasizing the evolutionary flexibility of cis-regulatory networks.