Blocks to retroviral replication by different TRIM5α proteins from several species. The replication of HIV-1 is blocked by TRIM5α from old world monkeys and owl monkeys, but not human and new world monkeys (left top panel). The replication of SIV is blocked by TRIM5α proteins from new world monkeys, but not from humans, old world monkeys, and owl monkeys (right top panel). The replication of N-MLV is prevented by TRIM5α proteins from dogs, pigs, cows, old world monkeys, and humans, but not mice (left bottom panel). The replication of EIAV is blocked by TRIM5α from human and old world monkeys, but not horses (right bottom panel). In all cases, arrows indicate no inhibition.