Expression site associated genes of Trypanosoma brucei rhodesiense.
Upstream of at least some telomere-linked genes for the variant surface glycoproteins (VSGs) of African trypanosomes are expression site associated genes (ESAGs) whose transcription is co-ordinated with the transcription of the adjacent VSG gene [Cully et al. (1985) Cell 42, 173-182]. The function of the corresponding ESAG proteins is not known. Here we show the sequences of two members of the ESAG-I family that are upstream of the VSG genes expressed in metacyclic variant antigen types 4 and 7 of Trypanosoma brucei rhodesiense. The corresponding metacyclic ESAG-I proteins of about 330 amino acids display extensive positional identity both with each other and with two other ESAG-I proteins of Trypanosoma brucei brucei. Only about 7% of the positions are occupied by a different amino acid in each of the four putative ESAG proteins while 40% of the positions are identical. Thus, the ESAG-I proteins are much more highly conserved than are the VSGs studied to date.
Son
H J
HJ
Department of Biochemistry, University of Iowa, Iowa City 52242.
Cook
G A
GA
Hall
T
T
Donelson
J E
JE
D000595:Amino Acid Sequence; D000818:Animals; D000940:Antigenic Variation; D001483:Base Sequence; D004247:DNA; D015342:DNA Probes; D005796:Genes; D015151:Immunoblotting; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D014158:Transcription, Genetic; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000276:immunology
D015342:DNA Probes; D008562:Membrane Glycoproteins; D004247:DNA