Fig. 8. Progenitors of the Svp lineage adopt a pericardial cell fate in numb,CycA double mutants. A2-A7 hemisegments of stage 13 embryos labeled for (A-D,G,H) Tinman (red) and Eve (green), or (E-F) Odd (red) and Eve (green). (A-D) Although both numb and CycA mutants exhibit four myocardial cells per hemisegment, only two express tinman (TMC) in CycA mutants (B) (asterisks indicate position of SMC), but in numb mutants (C) all four express tinman (no SMC form). In numb,CycA double mutants (D), two myocardial cells are formed, both expressing tinman; thus, no SMCs form. (E) The number of odd-expressing pericardial cells (OPC) is increased from four (Fig. 2E) to six in numb mutants. (F) In CycA mutants, only one OPC is formed (Fig. 2F), in CycA;numb double mutants, three OPCs are usually observed. (G) Overexpression of N(icd) not only increases the number of EPCs, but also reduces the number of the myocardial cells from six (Fig. 7E) to four, all of which exhibit TMC characteristics. (H) Overexpression of N(icd) in CycA mutants generates one EPC and the two myocardial cells (seen in Fig. 7F), both of which express tinman (TMC).