Fig. 6. Localized electroporation (LEP) of antisense thio-oligonucleotides to hydra laminin ß1 chain (LM) or hydra matrix metalloproteinase (MMP) into the apical pole of decapitated polyps results in a reversible inhibition of head regeneration. As monitored by whole-mount immunofluorescence, antisense oligos to LM blocked the appearance of laminin protein at the apical pole at 24 hours after LEP and decapitation (A). Sense oligos did not block the appearance of LM protein at the regenerating pole (B, arrows indicate reforming ECM). Antisense oligos to LM also blocks the appearance of hydra type I collagen (Col-I), as monitored as early as 36 hours and as late as 48 hours after decapitation with antibody to Col-I (C). Sense oligos to LM had no effect on the appearance of Col-I (D, arrows indicate reforming ECM). The area between the two arrows in B and D represents 100 µm.