TY - JOUR TI - Functional divergence of paralogous transcription factors supported the evolution of biomineralization in echinoderms AU - Khor, Jian Ming AU - Ettensohn, Charles A A2 - Tautz, Diethard VL - 6 PY - 2017 DA - 2017/11/20 SP - e32728 C1 - eLife 2017;6:e32728 DO - 10.7554/eLife.32728 UR - https://doi.org/10.7554/eLife.32728 AB - Alx1 is a pivotal transcription factor in a gene regulatory network that controls skeletogenesis throughout the echinoderm phylum. We performed a structure-function analysis of sea urchin Alx1 using a rescue assay and identified a novel, conserved motif (Domain 2) essential for skeletogenic function. The paralogue of Alx1, Alx4, was not functionally interchangeable with Alx1, but insertion of Domain 2 conferred robust skeletogenic function on Alx4. We used cross-species expression experiments to show that Alx1 proteins from distantly related echinoderms are not interchangeable, although the sequence and function of Domain 2 are highly conserved. We also found that Domain 2 is subject to alternative splicing and provide evidence that this domain was originally gained through exonization. Our findings show that a gene duplication event permitted the functional specialization of a transcription factor through changes in exon-intron organization and thereby supported the evolution of a major morphological novelty. KW - sea urchins KW - Alx1 transcription factor KW - skeletogenesis KW - gene duplication KW - evolution JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -