Lampreys, the jawless vertebrates, contain only two ParaHox gene clusters

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Lampreys, the jawless vertebrates, contain only two ParaHox gene clusters
Title:
Lampreys, the jawless vertebrates, contain only two ParaHox gene clusters
Other Titles:
Proceedings of the National Academy of Sciences
Keywords:
Publication Date:
22 August 2017
Citation:
ParaHox genes in lampreys Huixian Zhang, Vydianathan Ravi, Boon-Hui Tay, Sumanty Tohari, Nisha E. Pillai, Aravind Prasad, Qiang Lin, Sydney Brenner, Byrappa Venkatesh Proceedings of the National Academy of Sciences Aug 2017, 114 (34) 9146-9151; DOI: 10.1073/pnas.1704457114
Abstract:
ParaHox genes (Gsx, Pdx, and Cdx) are an ancient family of developmental genes closely related to the Hox genes. They play critical roles in the patterning of brain and gut. The basal chordate, amphioxus, contains a single ParaHox cluster comprising one member of each family, whereas nonteleost jawed vertebrates contain four ParaHox genomic loci with six or seven ParaHox genes. Teleosts, which have experienced an additional whole-genome duplication, contain six ParaHox genomic loci with six ParaHox genes. Jawless vertebrates, represented by lampreys and hagfish, are the most ancient group of vertebrates and are crucial for understanding the origin and evolution of vertebrate gene families. We have previously shown that lampreys contain six Hox gene loci. Here we report that lampreys contain only two ParaHox gene clusters (designated as α- and β-clusters) bearing five ParaHox genes (Gsxα, Pdxα, Cdxα, Gsxβ, and Cdxβ). The order and orientation of the three genes in the α-cluster are identical to that of the single cluster in amphioxus. However, the orientation of Gsxβ in the β-cluster is inverted. Interestingly, Gsxβ is expressed in the eye, unlike its homologs in jawed vertebrates, which are expressed mainly in the brain. The lamprey Pdxα is expressed in the pancreas similar to jawed vertebrate Pdx genes, indicating that the pancreatic expression of Pdx was acquired before the divergence of jawless and jawed vertebrate lineages. It is likely that the lamprey Pdxα plays a crucial role in pancreas specification and insulin production similar to the Pdx of jawed vertebrates.
License type:
Attribution 4.0 International (CC BY 4.0)
Funding Info:
We thank Michael Schorpp and Thomas Boehm for providing pancreatic tissue of brook lamprey, and Jonathan M. Wilson for sea lamprey pancreas cDNA. This work was supported by the Biomedical Research Council of the Agency for Science, Technology and Research of Singapore.
Description:
ISSN:
0027-8424
1091-6490