Table 1

Structural characteristics of Wukong, Wujin, and Wuneng in comparison with Tourist and Xbr

ElementSize, bpTIR, bpTarget site consensusA+T content, %−ΔG,* kcal/molCopies per genomeOrganism
Wukong 420–44017TAt/cA64–6990.9–109.72,200–3,000 Ae. aegypti
Wujin 18523TA57–5851.5–73.12,100 Ae. aegypti
Wuneng 256–25719TTAA/t6354.9–70.32,700 Ae. aegypti
Tourist 113–29914TAA53–8220.1–84.6>10,000 Zea mays
Xbr 46242TTAA67156.25,000 X. laevis
  • Only complete Wukong, Wujin, and Wuneng elements were used to calculate their sizes, A+T contents, and ΔG values. Data for Tourist elements were from Bureau and Wessler (1, 2). Xbr is a family of MITE-like elements found in Xenopus (8). Size, A+T content, and ΔG value were calculated according to the consensus sequence shown in ref. 8. The length of the element and the terminal inverted repeat does not include the putative target duplications. TIR, terminal inverted repeats. 

  • * The ΔG values for Wukong, Wujin, Wuneng, and Xbr were calculated using the default settings of FoldRNA of the GCG package (24), where the base pairing and stacking energies and the loop destabilizing energies were from Freier et al. (25) (1 kcal = 4.18 kJ). The ΔG values for Tourist were from Bureau and Wessler (1, 2) and were calculated using FoldRNA with the base pairing and stacking energies modified for DNA (28). Analysis of several sequences using both methods showed only 1–16% differences in the ΔG values.