The Pax Gene Family Encodes For Highly Conserved Dna...

Introduction The Pax gene family encodes for highly conserved DNA-binding transcription factors that play a vital role in embryonic development. All Pax proteins have a paired-box, DNA-binding domain of 128 amino acids located at the amino-terminal end, and is very highly conserved in Drosophila melanogaster, human, and mouse genes (Mansouri et al. 1996). Each different paralogous Pax gene has a crucial role in D. melanogaster and vertebrate development in terms of morphogenesis, organogenesis, cell differentiation, and oncogenesis (Mansouri et al. 1996). However, in this paper, the importance of Pax6’s discovery, mutations, and signaling pathway will be emphasized. It is worthy to note that Pax6 does not operate in a hierarchical linear signaling pathway but instead, in a massive network with numerous feedback loops. It is impossible to cover all possible feedback loops; therefore, the focus of the signaling pathway will be on the lens placode. The Pax6 gene was originally fo und in D. melanogaster corresponding to the eyeless locus (Mansouri et al. 1996). While Pax6 is most famous for its function eye development, it is also prevalent in the pancreas and nervous system development. Since Pax6 encodes a transcription factor that is involved in so many developmental pathways in the eye, pancreas, and nervous system, there is a wide spectrum of defects (Davis et al. 2008). The most common defect is aniridia (absence of the iris) which occurs due to a nonsense mutation