| Citation | Piet Borst is distinguished for his research on a wide range of subjects in biochemistry and molecular biology. Early work on mitochondrial function and biogenesis led to the discovery that 25 (micro) m DNA circles are the intact genomes of yeast mitochondria and to the isolation and characterization of the mitochondrial protein synthesizing apparatus. He has made numerous basic contributions to research on the replication and transcription of mitochondrial DNA in a variety of cells and has made extensive studies on the structure, function, replication, transcription and evolution of kinetoplast DNA (an unusual form of mitochondrial DNA) of trypanosomes. His more recent work on yeast mitochondrial DNA led to the precise correlation of the physical and the genetics maps, and to the discovery of introns in mitochondrial genes. He has studied the complex splicing steps required to remove these introns, and discovered the existence of circular RNA molecules in mitochondria. He has characterized many genes of yeast mitochondria by DNA sequencing. His most recent and significant work involves the elucidation of the mechanism of antigen variation in trypanosomes. He has shown that this is due to the differential expression of pre-existing genes which are activated by duplication and translocation to a special chromosomal region adjacent to a telomere placing them under the control of a strong promoter. He continues to analyse this most interesting biological phenomenon. |