Fig. 9. (A-T) Expression pattern of CsASH1. (A-O) Whole mounts; anterior is towards the top. (A-E) Cephalic lobe; (F-J) prosoma; (K-O) opisthosoma; (P-T) flat preparations of the fourth prosomal segments; anterior is towards the top, the black lines indicate the segmental borders. (A,F,K) At 120 hours, CsASH1 staining is visible in the cephalic lobe (arrow in A), in the anterior-most lateral regions of all hemisegments of the prosoma (F,P) and in the first opisthosomal segment (K). (B,G,L) At 130 hours, CsASH1 staining has extended posteriorly and medially in the prosoma (G, arrows in Q). The staining in the anterior-most lateral region that was visible in the prosoma and the first opisthosomal hemisegments before can now be seen in opisthosomal segments o2 to o4 (L). Additional expression domains can be also detected in the cephalic lobe. (C,H,M) At 160 hours, CsASH1 expression has decreased in the cephalic lobe (C) and in the second to sixth opisthosomal hemisegments (M). The RNA is now expressed in a lateral and a medial stripe of cells in the prosomal and the first opisthosomal hemisegments (H,M,arrows in R). (D,I,N) At 180 hours, new expression domains can be seen in the cephalic lobe (D, arrows). The former CsASH1 expression has disappeared in the prosoma and the first opisthosomal segment and a new medial expression domain is visible (I, arrow in S). The expression pattern in the opisthosoma reflects that seen before in the prosoma (N). CsASH1 is expressed weakly in the invaginating neuroectodermal cells (S, arrowheads). (E,J,O) At 220 hours, the medial expression domain has disappeared with the exception of the last three segments of the opisthosoma (O). CsASH1 is only weakly expressed in the invaginating cells (T, arrowhead). ped, pedipalpal segment; l1 to l4, walking legs 1 to 4 (corresponding to prosomal segments 3 to 6); o1 to o5, opisthosomal segments 1 to 5. Scale bar: 200 µm in A-O; 150 µm in P-T.