Fig. 5. MRG-1 is not required for the appearance of elongating RNA polymerase II in early PGCs. (A-H) Embryos (28-cell and 100-cell) triply stained with antibodies to RNA Pol II CTD phosphorylated on Ser2 (green) and PGL-1 (red) and with DAPI (blue). In both wild-type and mrg-1(qa6200) M-Z-embryos, phosphorylated Pol II was not detected in the germline blastomere P4 (A,C), but appeared in Z2 and Z3 (E,G). Scale bar: 10 µm.