par Matthyssens, G;Michiels, F;Hamers, Raymond 
;Pays, Etienne ;Steinert, Maurice
Référence Nature (London), 293, 5829, page (230-233)
Publication Publié, 1981
;Pays, Etienne ;Steinert, Maurice Référence Nature (London), 293, 5829, page (230-233)
Publication Publié, 1981
Article révisé par les pairs
| Résumé : | Gene duplication and transposition are known to be involved in the mechanism of antigenic variation in Trypanosoma brucei1-3. However, the structure of the antigens in question - the variant surface glycoproteins (VSGs) - is poorly defined. Limited sequencing data show extensive variation between the N-terminal amino acid sequences of different VSGs4,5, although serological studies indicate common antigenic determinants in the C-terminal portion (refs 6, 7 and N. Van Meirvenne, personal communication). More recently, the existence of a C-terminal hydrophobic tail, which is absent from the isolated glycoprotein, was reported8. We have now compared the messenger RNA sequences corresponding to the C-terminal 115 amino acids of two serologically different variants belonging to the same serodeme and report a 35% lack of homology (52% of amino acid positions). However, there is a large homologous area of 33 amino acids making up the C-terminus, which includes the 23-amino acid hydrophobic tail. Our data indicate that this extension is a universal feature in T. brucei VSGs. In addition, comparison of two isotypes (serologically similar VSGs) belonging to different serodemes showed almost complete nucleotide homology in the coding sequence of the C-terminal 115 amino acids. © 1981 Nature Publishing Group. |
