Accelerated evolution of 3'avian FOXE1 genes, and thyroid and feather specific expression of chicken FoxE1

Persistent Link:
http://hdl.handle.net/10150/610379
Title:
Accelerated evolution of 3'avian FOXE1 genes, and thyroid and feather specific expression of chicken FoxE1
Author:
Yaklichkin, Sergey Yu; Darnell, Diana; Pier, Maricela; Antin, Parker; Hannenhalli, Sridhar
Affiliation:
Penn Center for Bioinformatics, 1424 Blockley Hall, 423 Guardian Drive, University of Pennsylvania, Philadelphia, PA 19104 USA; Department of Cellular and Molecular Medicine, University of Arizona, PO Box 245217, 1656 E. Mabel, Tucson, AZ 85724 USA; Center for Bioinformatics and Computational Biology, University of Maryland, College Park, 3104G Biomolecular Sciences Building (#296), University of Maryland, College Park, MD 20742 USA
Issue Date:
2011
Publisher:
BioMed Central
Citation:
Yaklichkin et al. BMC Evolutionary Biology 2011, 11:302 http://www.biomedcentral.com/1471-2148/11/302
Journal:
BMC Evolutionary Biology
Rights:
© 2011 Yaklichkin et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0)
Collection Information:
This item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at repository@u.library.arizona.edu.
Abstract:
BACKGROUND:The forkhead transcription factor gene E1 (FOXE1) plays an important role in regulation of thyroid development, palate formation and hair morphogenesis in mammals. However, avian FOXE1 genes have not been characterized and as such, codon evolution of FOXE1 orthologs in a broader evolutionary context of mammals and birds is not known.RESULTS:In this study we identified the avian FOXE1 gene in chicken, turkey and zebra finch, all of which consist of a single exon. Chicken and zebra finch FOXE1 are uniquely located on the sex-determining Z chromosome. In situ hybridization shows that chicken FOXE1 is specifically expressed in the developing thyroid. Its expression is initiated at the placode stage and is maintained during the stages of vesicle formation and follicle primordia. Based on this expression pattern, we propose that avian FOXE1 may be involved in regulating the evagination and morphogenesis of thyroid. Chicken FOXE1 is also expressed in growing feathers. Sequence analysis identified two microdeletions in the avian FOXE1 genes, corresponding to the loss of a transferable repression domain and an engrailed homology motif 1 (Eh1) C-terminal to the forkhead domain. The avian FOXE1 proteins exhibit a significant sequence divergence of the C-terminus compared to those of amphibian and mammalian FOXE1. The codon evolution analysis (dN/dS) of FOXE1 shows a significantly increased dN/dS ratio in the avian lineages, consistent with either a relaxed purifying selection or positive selection on a few residues in avian FOXE1 evolution. Further site specific analysis indicates that while relaxed purifying selection is likely to be a predominant cause of accelerated evolution at the 3'-region of avian FOXE1, a few residues might have evolved under positive selection.CONCLUSIONS:We have identified three avian FOXE1 genes based on synteny and sequence similarity as well as characterized the expression pattern of the chicken FOXE1 gene during development. Our evolutionary analyses suggest that while a relaxed purifying selection is likely to be the dominant force driving accelerated evolution of avian FOXE1 genes, a few residues may have evolved adaptively. This study provides a basis for future genetic and comparative biochemical studies of FOXE1.
EISSN:
1471-2148
DOI:
10.1186/1471-2148-11-302
Version:
Final published version
Additional Links:
http://www.biomedcentral.com/1471-2148/11/302

Full metadata record

DC FieldValue Language
dc.contributor.authorYaklichkin, Sergey Yuen
dc.contributor.authorDarnell, Dianaen
dc.contributor.authorPier, Maricelaen
dc.contributor.authorAntin, Parkeren
dc.contributor.authorHannenhalli, Sridharen
dc.date.accessioned2016-05-20T09:05:29Z-
dc.date.available2016-05-20T09:05:29Z-
dc.date.issued2011en
dc.identifier.citationYaklichkin et al. BMC Evolutionary Biology 2011, 11:302 http://www.biomedcentral.com/1471-2148/11/302en
dc.identifier.doi10.1186/1471-2148-11-302en
dc.identifier.urihttp://hdl.handle.net/10150/610379-
dc.description.abstractBACKGROUND:The forkhead transcription factor gene E1 (FOXE1) plays an important role in regulation of thyroid development, palate formation and hair morphogenesis in mammals. However, avian FOXE1 genes have not been characterized and as such, codon evolution of FOXE1 orthologs in a broader evolutionary context of mammals and birds is not known.RESULTS:In this study we identified the avian FOXE1 gene in chicken, turkey and zebra finch, all of which consist of a single exon. Chicken and zebra finch FOXE1 are uniquely located on the sex-determining Z chromosome. In situ hybridization shows that chicken FOXE1 is specifically expressed in the developing thyroid. Its expression is initiated at the placode stage and is maintained during the stages of vesicle formation and follicle primordia. Based on this expression pattern, we propose that avian FOXE1 may be involved in regulating the evagination and morphogenesis of thyroid. Chicken FOXE1 is also expressed in growing feathers. Sequence analysis identified two microdeletions in the avian FOXE1 genes, corresponding to the loss of a transferable repression domain and an engrailed homology motif 1 (Eh1) C-terminal to the forkhead domain. The avian FOXE1 proteins exhibit a significant sequence divergence of the C-terminus compared to those of amphibian and mammalian FOXE1. The codon evolution analysis (dN/dS) of FOXE1 shows a significantly increased dN/dS ratio in the avian lineages, consistent with either a relaxed purifying selection or positive selection on a few residues in avian FOXE1 evolution. Further site specific analysis indicates that while relaxed purifying selection is likely to be a predominant cause of accelerated evolution at the 3'-region of avian FOXE1, a few residues might have evolved under positive selection.CONCLUSIONS:We have identified three avian FOXE1 genes based on synteny and sequence similarity as well as characterized the expression pattern of the chicken FOXE1 gene during development. Our evolutionary analyses suggest that while a relaxed purifying selection is likely to be the dominant force driving accelerated evolution of avian FOXE1 genes, a few residues may have evolved adaptively. This study provides a basis for future genetic and comparative biochemical studies of FOXE1.en
dc.language.isoenen
dc.publisherBioMed Centralen
dc.relation.urlhttp://www.biomedcentral.com/1471-2148/11/302en
dc.rights© 2011 Yaklichkin et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0)en
dc.titleAccelerated evolution of 3'avian FOXE1 genes, and thyroid and feather specific expression of chicken FoxE1en
dc.typeArticleen
dc.identifier.eissn1471-2148en
dc.contributor.departmentPenn Center for Bioinformatics, 1424 Blockley Hall, 423 Guardian Drive, University of Pennsylvania, Philadelphia, PA 19104 USAen
dc.contributor.departmentDepartment of Cellular and Molecular Medicine, University of Arizona, PO Box 245217, 1656 E. Mabel, Tucson, AZ 85724 USAen
dc.contributor.departmentCenter for Bioinformatics and Computational Biology, University of Maryland, College Park, 3104G Biomolecular Sciences Building (#296), University of Maryland, College Park, MD 20742 USAen
dc.identifier.journalBMC Evolutionary Biologyen
dc.description.collectioninformationThis item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
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