The vertebrate makorin ubiquitin ligase gene family has been shaped by large-scale duplication and retroposition from an ancestral gonad-specific, maternal-effect gene

BMC Genomics

Research Article

Jean-Francois Baroiller¹  Helena D'Cotta¹  Delphine Galiana-Arnoux²  Amandine Darras²  Jean-Nicolas Volff²  Astrid Böhne² 

[1] CIRAD, Upr20, Dept. Persyst, Campus International de Baillarguet, Montpellier, France;Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS, INRA, Ecole Normale Supérieure de Lyon, Lyon, France;

关键词: Zinc Finger;    Ring Domain;    Zygotic Genome Activation;    Elephant Shark;    Therian Mammal;   

DOI  :  10.1186/1471-2164-11-721

 received in 2010-07-29, accepted in 2010-12-20,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundMembers of the makorin (mkrn) gene family encode RING/C3H zinc finger proteins with U3 ubiquitin ligase activity. Although these proteins have been described in a variety of eukaryotes such as plants, fungi, invertebrates and vertebrates including human, almost nothing is known about their structural and functional evolution.ResultsVia partial sequencing of a testis cDNA library from the poeciliid fish Xiphophorus maculatus, we have identified a new member of the makorin gene family, that we called mkrn4. In addition to the already described mkrn1 and mkrn2, mkrn4 is the third example of a makorin gene present in both tetrapods and ray-finned fish. However, this gene was not detected in mouse and rat, suggesting its loss in the lineage leading to rodent murids. Mkrn2 and mkrn4 are located in large ancient duplicated regions in tetrapod and fish genomes, suggesting the possible involvement of ancestral vertebrate-specific genome duplication in the formation of these genes. Intriguingly, many mkrn1 and mkrn2 intronless retrocopies have been detected in mammals but not in other vertebrates, most of them corresponding to pseudogenes. The nature and number of zinc fingers were found to be conserved in Mkrn1 and Mkrn2 but much more variable in Mkrn4, with lineage-specific differences. RT-qPCR analysis demonstrated a highly gonad-biased expression pattern for makorin genes in medaka and zebrafish (ray-finned fishes) and amphibians, but a strong relaxation of this specificity in birds and mammals. All three mkrn genes were maternally expressed before zygotic genome activation in both medaka and zebrafish early embryos.ConclusionOur analysis demonstrates that the makorin gene family has evolved through large-scale duplication and subsequent lineage-specific retroposition-mediated duplications in vertebrates. From the three major vertebrate mkrn genes, mkrn4 shows the highest evolutionary dynamics, with lineage-specific loss of zinc fingers and even complete gene elimination from certain groups of vertebrates. Comparative expression analysis strongly suggests that the ancestral E3 ubiquitin ligase function of the single copy mkrn gene before duplication in vertebrates was gonad-specific, with maternal expression in early embryos.

【 授权许可】

Unknown   
© Böhne et al; licensee BioMed Central Ltd. 2010. This article is published under license to 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), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.