Figure 8. Sir2A, but Not PfSir2B Has a Role in Telomere Length Regulation.
Genomic DNA from wildtype (3D7), ΔPfSir2A, and ΔPfSir2B was digested with four frequently cutting restriction enzymes that do not cut telomeric repeats. Samples were run on 1% agarose gel and probed with telomeric repeat-labelled with 32P. Telomere length is seen as a smear as telomere lengths vary between chromosomes and within a population telomere. 3D7 parasites have telomere lengths of between 1–2 kB. Whereas upon disruption of PfSir2A but not PfSir2B, telomere length approximately doubles in size. PfSir2B-disrupted parasites have several distinct bands of a length that correspond to nonlengthened telomeres. It is also possible that they represent telomeric repeats that have recombined into chromosome internal locations and thus are not able to lengthen.