TY - JOUR
T1 - Evolutionary origins of Pax6 control of crystallin genes
AU - Cvekl, Ales
AU - Zhao, Yilin
AU - McGreal, Rebecca
AU - Xie, Qing
AU - Gu, Xun
AU - Zheng, Deyou
N1 - Publisher Copyright:
© The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
PY - 2017/8/1
Y1 - 2017/8/1
N2 - The birth of novel genes, including their cell-specific transcriptional control, is a major source of evolutionary innovation. The lens-preferred proteins, crystallins (vertebrates: a-and b/c-crystallins), provide a gateway to study eye evolution. Diversity of crystallins was thought to originate from convergent evolution through multiple, independent formation of Pax6/PaxB-binding sites within the promoters of genes able to act as crystallins. Here, we propose that aB-crystallin arose from a duplication of small heat shock protein (Hspb1-like) gene accompanied by Pax6-site and heat shock element (HSE) formation, followed by another duplication to generate the aA-crystallin gene in which HSE was converted into another Pax6-binding site. The founding b/c-crystallin gene arose from the ancestral Hspb1-like gene promoter inserted into a Ca2+-binding protein coding region, early in the cephalochordate/tunicate lineage. Likewise, an ancestral aldehyde dehydrogenase (Aldh) gene, through multiple gene duplications, expanded into a multigene family, with specific genes expressed in invertebrate lenses (X-crystallin/Aldh1a9) and both vertebrate lenses (g-crystallin/Aldh1a7 and Aldh3a1) and corneas (Aldh3a1). Collectively, the present data reconstruct the evolution of diverse crystallin gene families.
AB - The birth of novel genes, including their cell-specific transcriptional control, is a major source of evolutionary innovation. The lens-preferred proteins, crystallins (vertebrates: a-and b/c-crystallins), provide a gateway to study eye evolution. Diversity of crystallins was thought to originate from convergent evolution through multiple, independent formation of Pax6/PaxB-binding sites within the promoters of genes able to act as crystallins. Here, we propose that aB-crystallin arose from a duplication of small heat shock protein (Hspb1-like) gene accompanied by Pax6-site and heat shock element (HSE) formation, followed by another duplication to generate the aA-crystallin gene in which HSE was converted into another Pax6-binding site. The founding b/c-crystallin gene arose from the ancestral Hspb1-like gene promoter inserted into a Ca2+-binding protein coding region, early in the cephalochordate/tunicate lineage. Likewise, an ancestral aldehyde dehydrogenase (Aldh) gene, through multiple gene duplications, expanded into a multigene family, with specific genes expressed in invertebrate lenses (X-crystallin/Aldh1a9) and both vertebrate lenses (g-crystallin/Aldh1a7 and Aldh3a1) and corneas (Aldh3a1). Collectively, the present data reconstruct the evolution of diverse crystallin gene families.
KW - Aldehyde dehydrogenase
KW - Crystallin
KW - Eye evolution
KW - Heat shock responsive element
KW - Lens
KW - Pax6
KW - Small heat shock protein
UR - http://www.scopus.com/inward/record.url?scp=85032006787&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85032006787&partnerID=8YFLogxK
U2 - 10.1093/gbe/evx153
DO - 10.1093/gbe/evx153
M3 - Article
C2 - 28903537
AN - SCOPUS:85032006787
SN - 1759-6653
VL - 9
SP - 2075
EP - 2092
JO - Genome Biology and Evolution
JF - Genome Biology and Evolution
IS - 8
ER -