Article ID Journal Published Year Pages File Type
2194547 Mechanisms of Development 2013 25 Pages PDF
Abstract

•Midline (Mid) is expressed in photoreceptor neurons.•Mid is expressed in sensory organ precursor cells and specifies their neuronal fates.•mid Collaborates genetically with extramacrochaetae, atonal and senseless.•p35 suppresses apoptosis in mid mutant imaginal eye discs.

We report that the T-box transcription factor Midline (Mid), an evolutionary conserved homolog of the vertebrate Tbx20 protein, functions within the Notch–Delta signaling pathway essential for specifying the fates of sensory organ precursor (SOP) cells. These findings complement an established history of research showing that Mid regulates the cell-fate specification of diverse cell types within the developing heart, epidermis and central nervous system. Tbx20 has been detected in unique neuronal and epithelial cells of embryonic eye tissues in both mice and humans. However, the mechanisms by which either Mid or Tbx20 function to regulate cell-fate specification or other critical aspects of eye development including cell survival have not yet been elucidated. We have also gathered preliminary evidence suggesting that Mid may play an indirect, but vital role in selecting SOP cells within the third-instar larval eye disc by regulating the expression of the proneural gene atonal. During subsequent pupal stages, Mid specifies SOP cell fates as a member of the Notch–Delta signaling hierarchy and is essential for maintaining cell viability by inhibiting apoptotic pathways. We present several new hypotheses that seek to understand the role of Mid in regulating developmental processes downstream of the Notch receptor that are critical for specifying unique cell fates, patterning the adult eye and maintaining cellular homeostasis during eye disc morphogenesis.

Related Topics
Life Sciences Biochemistry, Genetics and Molecular Biology Cell Biology
Authors
, , , , , , , , , ,