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Artificial Linear Mini-Chromosomes for Trypanosoma Brucei

1996; Oxford University Press; Volume: 24; Issue: 4 Linguagem: Inglês

10.1093/nar/24.4.668

1362-4962

Pradeep K. Patnaik, Nancy Axelrod, L. H. T. Van der Ploeg, George Cross,

T-cell and Retrovirus Studies

We have constructed artificial linear mini-chromosomes for the parasitic protozoan Trypanosoma brucei.These chromosomes exist at ∼2 copies per cell, are indefinitely stable under selection but are lost from 50% of the transformed population in ∼7 generations when grown in the absence of selective pressure.Consistent with results obtained earlier with natural chromosomes in T.brucei, the telomeres on these artificial chromosomes grow, adding ∼1-1.5 telomeric repeats per generation.The activity of a procyclic acidic repetitive protein (parp) gene promoter on these elements is unaffected by its proximity to a telomere, implying the lack of a telomere-proximal position effect (TPE) in procyclic trypanosomes.Among other things, these autonomously replicating dispensable genetic elements will provide a defined system for the study of nuclear DNA replication, karyotypic plasticity and other aspects of chromosomal behavior in this ancient eukaryotic lineage.