PUBLICATION

Gel-forming mucins appeared early in metazoan evolution

Authors
Lang, T., Hansson, G.C., and Samuelsson, T.
ID
ZDB-PUB-120813-1
Date
2007
Source
Proceedings of the National Academy of Sciences of the United States of America   104(41): 16209-16214 (Journal)
Registered Authors
Keywords
bioinformatics, von Willebrand domain, SEA domain, protein evolution, mucus
MeSH Terms
  • Animals
  • Chordata, Nonvertebrate/genetics
  • Evolution, Molecular*
  • Gels
  • Humans
  • Membrane Glycoproteins/chemistry
  • Membrane Glycoproteins/genetics
  • Mucins/chemistry
  • Mucins/genetics*
  • Phylogeny
  • Protein Structure, Tertiary
  • Strongylocentrotus purpuratus/genetics
  • Xenopus/genetics
  • Xenopus Proteins/chemistry
  • Xenopus Proteins/genetics
  • von Willebrand Factor/chemistry
  • von Willebrand Factor/genetics
PubMed
17911254 Full text @ Proc. Natl. Acad. Sci. USA
Abstract

Mucins are proteins that cover and protect epithelial cells and are characterized by domains rich in proline, threonine, and serine that are heavily glycosylated (PTS or mucin domains). Because of their sequence polymorphism, these domains cannot be used for evolutionary analysis. Instead, we have made use of the von Willebrand D (VWD) and SEA domains, typical for mucins. A number of animal genomes were examined for these domains to identify mucin homologues, and domains of the resulting proteins were used in phylogenetic studies. The frog Xenopus tropicalis stands out because the number of gel-forming mucins has markedly increased to at least 25 as compared with 5 for higher animals. Furthermore, the frog Muc2 homologues contain unique PTS domains where cysteines are abundant. This animal also has a unique family of secreted mucin-like proteins with alternating PTS and SEA domains, a type of protein also identified in the fishes. The evolution of the Muc4 mucin seems to have occurred by recruitment of a PTS domain to AMOP, NIDO, and VWD domains from a sushi domain-containing family of proteins present in lower animals, and Xenopus is the most deeply branching animal where a protein similar to the mammalian Muc4 was identified. All transmembrane mucins seem to have appeared in the vertebrate lineage, and the MUC1 mucin is restricted to mammals. In contrast, proteins with properties of the gel-forming mucins were identified also in the starlet sea anemone Nematostella vectensis, demonstrating an early origin of this group of mucins.

Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping