Nucleic Acids Research, 1984, Vol. 12, No. 23 9051-9066
© 1984
MOLECULAR BIOLOGY |
The IsTat 1.3 VSG multigene family in Trypanosoma bruceui: retention of the expression linked copy through multiple antigenic switches
Issaquah Health Research Institute 1595 N.W. Gilman Blvd., Issaquah, WA 98027 1Department of Biochemistry, University of Washington Seattle, WA 98195, USA
Received May 1, 1984. Revised November 8, 1984. Accepted November 8, 1984.
In the IsTaR 1 serodeme of T. brucei the 3 variant surface glycoprotein (VSG) gene family contains about 10 members, one of which has a telomeric location on a minichromosome. The expression linked copy (ELC) of the 3 VSG gene which occurs in an antigenic variant expressing the 3 VSG, also has a telomeric location but unlike the minichromosomal 3 VSG gene has restriction sites upstream from the 5' barren region. This ELC is retained on the same telomere in (i) a subsequent variant that expresses a telomeric 7 VSG ELC and in (ii) relapse variants and procyclic forms derived from variant antigenic types (VATs) 3 and 7. The 7 ELC has a restriction map upstream from the 5' barren region that differs from, but is similar to, that of the 3 ELC. These data indicate that the 3 and 7 ELCs are on different telomeres when expressed.
*Current address: Naval Biosciences Laboratory, 140 Warren Hall, University of California, Berkeley, CA 94720, USA