PUBLICATION

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

Authors
Bohne, A., Darras, A., D'Cotta, H., Baroiller, J.F., Galiana-Arnoux, D., and Volff, J.N.
ID
ZDB-PUB-101222-48
Date
2010
Source
BMC Genomics   11: 721 (Journal)
Registered Authors
Keywords
none
MeSH Terms
  • Amino Acid Sequence
  • Animals
  • Evolution, Molecular
  • Female
  • Gene Duplication/genetics*
  • Gene Expression Profiling
  • Gene Expression Regulation, Developmental
  • Gonads/metabolism*
  • Humans
  • Mice
  • Molecular Sequence Data
  • Multigene Family/genetics*
  • Nerve Tissue Proteins/chemistry
  • Nerve Tissue Proteins/genetics*
  • Nerve Tissue Proteins/metabolism
  • Organ Specificity/genetics
  • Phylogeny*
  • Poecilia/genetics*
  • Protein Structure, Tertiary
  • Rats
  • Retroelements/genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Synteny/genetics
  • Ubiquitin-Protein Ligases/chemistry
  • Ubiquitin-Protein Ligases/genetics
  • Ubiquitin-Protein Ligases/metabolism
  • Zinc Fingers
PubMed
21172006 Full text @ BMC Genomics
Abstract
BACKGROUND: Members 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. RESULTS: Via 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 was found to be very 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. CONCLUSION: Our 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.
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Human Disease / Model
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