tokens: Site - directed mutagenesis was conducted to investigate the functional significance of this element and the 3 ' minus - strand terminal sequence " 3 ' - OH - CCCUAU , " which contains the minus - strand 3 ' - end sequence " 3 ' - OH - CC ( 1 - 2 ) ( A / U ) ( A / U ) ( A / U ) " found in all carmovirus RNAs .