Regulation of Thoracic Segment-Specific zfh1 Expression by Ultrabithorax and Abdominal A in Drosophila melanogaster

Abstract

Zinc finger homeodomain1 (zfh1) encodes a transcription factor containing zinc fingers and is expressed in the central nervous system (CNS) and in various mesodermal lineages, suggesting its pleiotropic functions. However, regulation of zfh1 expression specifically in the thorax remains unknown. In this study, we examined how the embryonic spatial expression pattern of zfh1 is established and regulated. Although zfh1 was co-expressed in many neurons and glia, zfh1 that was specifically expressed in the thorax was not overlapped with the marker proteins that label neurons or glia, suggesting that the thorax-specific cells showing zfh1 expression are not neurons or glia. When twist was knocked down, thorax-specific zfh1 expression was eliminated, suggesting that thorax-specific cells are mesodermally derived. zfh1 was ectopically expressed in Ultrabithorax (Ubx) or Ubx and abdominal-A (abd-A) double mutant embryos, suggesting that the normal UBX and ABD-A repress zfh1 in the abdominal segments. These results indicate that Twist activates thorax-specific expression of zfh1, and that UBX and ABD-A repress zfh1 expression in the abdomen, allowing the thorax-specific expression of zfh1.