The invention relates to a retroviral particle comprising a Gag polyprotein-derived protein, an envelope protein, optionally an integrase and at least two encapsidated non-viral RNAs, each of said encapsidated non-viral RNAs containing an RNA sequence of interest linked to an encapsidation sequence, each encapsidation sequence being recognized by a binding domain that is introduced into the Gag polyprotein-derived protein and/or into the integrase; furthermore, at least one of the sequences of interest of the encapsidated non-viral RNAs comprises a portion coding for a nuclease.