What does the cryptic crossword clue "Sign put up in Tokyo, electrified (3)" mean?

The definition is "Sign". The wordplay uses hidden reversed. Hidden reversed in "sign put up in tokyO, ELectrified" The answer is Leo.

Sign put up in Tokyo, electrified (3)

Telegraph Prize Cryptic #3069 | 16 Down | 2020-08-16 flower