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Identification of Bombyx atonal and functional comparison with the Drosophila atonal proneural factor in the developing fly eye
Author(s) -
Yu Linlin,
Zhou Qingxiang,
Zhang Chuanxi,
Pigi Francesca
Publication year - 2012
Publication title -
genesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.093
H-Index - 110
eISSN - 1526-968X
pISSN - 1526-954X
DOI - 10.1002/dvg.20816
Subject(s) - biology , proneural genes , ectopic expression , transcription factor , microbiology and biotechnology , bombyx mori , neurogenesis , drosophila melanogaster , eye development , phenotype , bombyx , atf3 , gene , genetics , gene expression , promoter
The proneural genes are fundamental regulators of neuronal development in all metazoans. A critical role of the fly proneural factor Atonal (Ato Dm ) is to induce photoreceptor neuron formation in Drosophila , whereas its murine homolog, Atonal7 Mm (aka Ath5) is essential for the development of the ganglion cells of the vertebrate eye. Here, we identify the Bombyx mori ato homolog ( ato Bm ). In a pattern strikingly reminiscent of ato Dm , the ato Bm mRNA is expressed as a stripe in the silkworm eye disc. Its DNA‐binding and protein‐protein interaction domain is highly homologous to the Ato Dm bHLH. Targeted expression of Ato Bm in the endogenous ato Dm pattern rescues the eyeless phenotype of the fly ato 1 mutant and its ectopic expression induces similar gain‐of‐function phenotypes as Ato Dm . Rescue experiments with chimeric proteins show that the non‐bHLH portion of Ato Bm (N‐region) can effectively substitute for the corresponding region of the fly transcription factor, even though no apparent conservation can be found at the amino acid level. On the contrary, the highly similar bHLH domain of Ato Bm cannot similarly substitute for the corresponding region of Ato Dm . Thus, the bHLH Bm domain requires the Ato Bm N‐region to function effectively, whereas the bHLH Dm domain can operate well with either N‐region. These findings suggest a role for the non‐bHLH portion of Ato proteins in modulating the function of the bHLH domain in eye neurogenesis and implicate specific aa residues of the bHLH in this process. genesis 50:393–403, 2012. © 2011 Wiley Periodicals, Inc.