An uglier solution, just to be complete: 

$k = 0; $string=~s@(?:<(?{++$k})|>(?{--$k}))*([^<>]*)@$k?uc($1):$1@ge;

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In reply to Re: I don't remember regex seeming this hard before by ambrus
in thread I don't remember regex seeming this hard before by danderson

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