Convergent evolution of cysteine-rich proteins in feathers and hair

BMC Evolutionary Biology

Research Article

Marcela Hermann¹  Veronika Mlitz²  Erwin Tschachler²  Bettina Strasser²  Leopold Eckhart² 

[1] Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria;Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Lazarettgasse 14, 1090, Vienna, Austria;

关键词: Feathers;    Evolution;    Epidermis;    Epidermal differentiation complex;    Keratin-associated protein;    Cysteine-rich protein;   

DOI  :  10.1186/s12862-015-0360-y

 received in 2015-01-15, accepted in 2015-04-24,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundFeathers and hair consist of cornified epidermal keratinocytes in which proteins are crosslinked via disulfide bonds between cysteine residues of structural proteins to establish mechanical resilience. Cysteine-rich keratin-associated proteins (KRTAPs) are important components of hair whereas the molecular components of feathers have remained incompletely known. Recently, we have identified a chicken gene, named epidermal differentiation cysteine-rich protein (EDCRP), that encodes a protein with a cysteine content of 36%. Here we have investigated the putative role of EDCRP in the molecular architecture and evolution of feathers.ResultsComparative genomics showed that the presence of an EDCRP gene and the high cysteine content of the encoded proteins are conserved among birds. Avian EDCRPs contain a species-specific number of sequence repeats with the consensus sequence CCDPCQ(K/Q)(S/P)V, thus resembling mammalian cysteine-rich KRTAPs which also contain sequence repeats of similar sequence. However, differences in gene loci and exon-intron structures suggest that EDCRP and KRTAPs have not evolved from a common gene ancestor but represent the products of convergent sequence evolution. mRNA in situ hybridization demonstrated that chicken EDCRP is expressed in the subperiderm layer of the embryonic epidermis and in the barbule cells of growing feathers. This expression pattern supports the hypothesis that feathers are evolutionarily derived from the subperiderm.ConclusionsThe results of this study suggest that convergent sequence evolution of avian EDCRP and mammalian KRTAPs has contributed to independent evolution of feathers and hair, respectively.

【 授权许可】

Unknown   
© Strasser et al.; licensee BioMed Central. 2015. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.