Table 2.

Main utilizations of homeoproteins, homeoprotein-derived peptides and homeoprotein antagonists in the regulation of physiological functions.

Tool	Model	Target
Penetratin-LINE1-siRNA	Mouse	Parkinson’s disease
EN1/2	Mouse	Parkinson’s disease
	Mouse	Amyotrophic lateral sclerosis
	Macaque	Parkinson’s disease
OTX2	Mouse	Glaucoma
OTX2 antagonists	Mouse	Amblyopia
	Mouse	Anxiety-like behavior

Penetratin, a cell-penetrating peptide corresponding to the third helix of the Antennapedia homeodomain has been widely used for the in vitro and in vivo internalization of a large number of peptides, phospho-peptides, and oligonucleotides. Here is recalled the in vivo use of Penetratin to internalize in midbrain neurons a siRNA targeting the Orf2p sequence present in the LINE-1 polycistronic mRNA. OTX2 antagonists used are single-chain anti-OTX2 antibodies and an OTX2-derived peptide competing for OTX2 binding to PV-cell extracellular matrix and its ensuing internalization. See references in text.