Mucin CYS domains are ancient and highly conserved modules that evolved in concert

作者：Desseyn Jean Luc^*

来源：Molecular Phylogenetics and Evolution, 2009, 52(2): 284-292.

DOI：10.1016/j.ympev.2009.03.035

• Gel-forming mucin
• Mucus
• CYS domain
• MUC2
• MUC5B
• MUC5AC
• Coding repeats
• Concerted evolution

Background: Many large secreted gel-forming mucins contain multiple copies of a "naked" cysteine-enriched domain (CYS domain) that interrupt or are adjacent to mucin domains (Ser/Thr/Pro regions). There is less similarity of homologous CYS sequences between species than there is across CYS repeats within species. These CYS domains are likely implicated in reversible mucin-mucin interactions that play a central role in mucus properties.
Results: The use of multiple genome sequences in a comparative analysis of CYS sequences identified new mucins containing the CYS domain in various species. Furthermore, analysis showed that this domain is at least 650 million-year old and that CYS sequences evolved under strong selective pressure in concerted fashion in all species examined by two mechanisms that never coexist within a given gene: either multiplication of exons encoding CYS modules or successive intra-exonic duplications.
Conclusion: The CYS sequences appear to have undergone concerted evolution with a high selective pressure to conserve cysteine and other amino acid residues. This domain is the best-conserved domain in secreted mucins pointing toward an important common function in many different organisms.

• 出版日期2009-8