Figure_3.tif (226.6 kB)
Human CCA-adding enzyme is able to repair damaged CCA ends of tRNAs.
figure
posted on 2013-08-29, 07:57 authored by Andreas Czech, Sandra Wende, Mario Mörl, Tao Pan, Zoya Ignatova(A) Total HeLa tRNAs and (B) internally radioactively labeled yeast tRNAPhe were incubated successively with angiogenin and human CCA-adding enzyme. Subsequently to the angiogenin treatment (4 h), T4 polynucleotide kinase (PNK) (45 min) was added which converts the 2′,3′-cyclophosphate ends [42] generated by the angiogenin cleavage to free 3′OH. After purification tRNAs were subjected to treatment with the CCA-adding enzyme (30 min). The 3′-CCA end integrity of the HeLa tRNAs was determined with the fluorescent oligonucleotide (Figure 1A, schematic inset). tRNAPhe lacking the terminal 3′-adenosine (tRNAPheCC) served as a control. The numbers on the left denote the DNA ladder in nt.