Fig. 8. Chimera analysis of actin79B^R291H and GFPactin88F, two proteins specifically incorporated into or excluded from Z-lines. To determine, whether the single amino acid change in actin79B^R291H determined its preference for Z-lines, and to determine which residues in GFPactin88F prevent its incorporation into Z-lines, we exchanged the N-terminal 149 amino acid between the two proteins. (A-D) The C-terminal half of GFPactin88F excludes the chimeric protein from Z-lines (A,C), whereas the C terminus of actin79B^R291H brings the N-terminal half of GFPactin88F into Z-lines (B,D). (A,B) GFPactin in third instar larval body wall muscles, (C,C',D,D') adult indirect flight muscles (green in C and D); the phalloidin channel is shown in C and D (red) and in C''and D''.