Atlus has announced that it’s upcoming title Persona 4 Arena Ultimax will not be region locked in North and South America, so an North America and South American version of the game should work for their respective consoles on either side:

Persona®4 Arena Ultimax, the upcoming fighting game from ATLUS will not be region locked for the Americas and will be available this fall for the PlayStation®3 and Xbox 360®; pre-orders and all first-run editions will include a collectible Teddie bop bag and Set #1 of the iconic Persona Tarot cards. (Set #2 will be included with Persona Q: Shadow of the Labyrinth.) This follows the recent announcement that playable DLC character Tohru Adachi will be offered for free the first week after the game’s launch.