Another approach that avoids the regex engine:

$s = 'message-center-db: "http://message-center-db-1b.message-center-d
+b.svc.cluster.local"';;

substr( $s, 0, index( $s, ':' ) ) =~ tr[-][_];;

print $s;;
message_center_db: "http://message-center-db-1b.message-center-db.svc.
+cluster.local"

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In reply to Re: Repeated substitution on 1 side of a line only by BrowserUk
in thread Repeated substitution on 1 side of a line only by dspivey

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