Figure 1. ATHs represent a functionally distinct proneural group.

(A) Alignment of bHLH domains of the ATHs used in this study. The bHLH domains of the three proneural TF families are characterized by the presence of family-specific AA (marked with * and ^∨). Asterisks: AA distinguishing ATHs from members of the Neurogenin family (Quan et al., 2004). (B) Phylogenetic position of the selected homologues and evolutionary relationship of the control proteins. The black tree shows the phylogeny of the organisms. The red dashed tree shows the relationships between protein families. The diagrams show the primary structures of the proteins; the bold box is the bHLH domain, numbers indicate the length of the protein outside the bHLH domain. Green tick: homozygous viable stocks , orange tick: semi-viable, red cross: absence of unbalanced flies. Dm: Drosophila melanogaster; Mm: Mus musculus; Bf: Branchiostoma floridae; Pd: Platynereis dumerilii; Aq: Amphimedon queenslandica. (C) Schema of the improved IMAGO approach (Choi et al., 2009). See also Figure 1—figure supplement 1.

DOI: http://dx.doi.org/10.7554/eLife.26402.002

Figure 1—figure supplement 1. Upon replacement in ato endogenous locus, all ATHs and AqbHLH1 rescue the lethality caused by loss of ato in the fruit fly.

(A) PCR reactions (iii) with the primer combinations (i) that result in a product only if the ATH (ii) or ato (ii’) is present in the template. Balanced and unbalanced flies were processed in parallel. (B) Anti-ELAV and anti-Ato immunostainings on late L3 eye-antennal discs of the indicated genotypes. Balanced and unbalanced flies were processed in parallel. Note that the magnification is not constant across all samples.

DOI: http://dx.doi.org/10.7554/eLife.26402.003