2.9 Cell-penetrating peptide identification
The homeodomain sequence of IRX4 was subjected to the CPPsite 2.0, a database of cell-penetrating peptides60. CPP site 2.0 contains experimentally validated cell-penetrating peptides and this server was used to determine the efficacy of IRX4 sequence to be considered in that category. SkipCPP-Pred was used to predict the sequence having the highest cell-penetrating potential61. SkipCPP-Pred (http://server.malab.cn/SkipCPP-Pred/Index.html) is a sequence-based computational predictor of cell-penetrating peptides that uses an algorithm k-skip n-gram combined with a random forest classifier.