LacZ staining is first detected in both Z1.pp and Z4.aa and is seen in Z1.ppp, Z4.aaa, Z1.ppa and Z4.aap. All four cells continue to express until the middle of the L2 stage during AC/VU decision and then expression is restricted to either Z1.ppp or Z4.aaa, with expression observed in presumptive VU (Z1.ppa and Z4.aap) but not in presumptive AC. This is consistent with GFP fluorescence observed. lin-12
::lacZ staining disappears in the VUs; staining reappears in their daughters just after division. The level of lin-12
::lacZ expression from early L2 until the Vulva Precursor Cells (VPCs) divide in the L3 is uniform in all 6 VPCs. lin-12
::lacZ reporter is also expressed in all twelve of the granddaughters of the VUs. There appears to be a time during the early L3 stage when the VUs no longer express the lin-12
::lacZ reporter gene. During L3, beta-gal activity is detected in two sheath cells in each gonad arm: sheath cells No. 1 (Z1.paaa, Z1.apa, Z4.pap, and Z4.appp). During early L4 stage, eight more sheath cells express the transgene: sheath cells No. 2 (Z1.paapaaa, Z1.appaaa, Z4.paappp, and Z4.appappp) and sheath cells No. 3 (Z1.paapaap, Z1.appaap, Z4.paappa, and Z4.appappa). Staining is almost always observed in sheath cells No. 1 in the L3 and L4 stages as well as in the young adult. Only a subset of animals consistently express the reporter gene in sheath cells No. 2. Staining in sheath cells No. 3 are never detected once the nuclei have migrated for out along the arm. Staining is observed in 12 sheath cells during the late L3/early L4 stages soon after they are born. As the cells move out the gonad arm, staining is only detected in one member of pair No. 1 and one member of pair No. 2 in each arm. Staining is detected during L4 in up to eight spermathecal cells [Z1.papaa(a/p) (d/v), Z4.apaaa(a/p)(d/v), Z1.pappp(a/p)(d/v) and Z4.apapp(a/p)(d/v)] in each arm. The progenitors of these cells [Z1.papaa(a/p), Z4.apaaa(a/p), Z1.pappp(a/p) and Z4.apapp(a/p)] also express the reporter gene. During the L2 and early L3 stages, lin-12
::lacZ is expressed in all six VPCs. LacZ staining is detected in all 12 daughters of the VPCs (Pn.px stage), and is then restricted to P5.ppa, P5.ppp, P7.paa and P7.pap. High level of GFP expression is seen in the daughters of P5.p and P7.p but not in the daughters of p6
.p. Variable level of GFP is detected in the daughters of P3,p, P4.p and P8.p. In the VPC granddaughters GFP is detected in P5.ppa, P5.ppp, P7.paa and P7.pap. Weak staining is detected in two of the granddaughters of P5.p and P7.p, the L cells, but is undetected in their progeny. Expression is always detected in the other two granddaughters of P5.p and P7.p, the N and T cells. There is no staining in the T descendants of P6.p cells. The N cells do not divide and staining is detected in both N cells throughout vulval morphogenesis in the L4 stage and in young adults. Staining can be detected in the T daughters in the L4 stage and in young adults. The parents of the SM/bm precursor cells; M.vlp and M.vrp and their dorsal equivalents, M.dlp and M.drp all express lin-12
reporter gene. After division of the parent cells, the SM/bm precursor cells and their dorsal equivalents also express the reporter gene as do the sisters of these cells. Expression is detected in both the SM and bm cells on the left and right sides of the animal. Staining persists in these cells on the ventral side even after it is no longer detectable in the cells of the dorsal side. [M.vrpa, M.vlpa, M.vrpp, M.vlpp, M.drpa, M.dla, M.drpp and M.dlpp]. Expression is detected in a discrete subset of cells during embryogenesis. Staining was only observed in pairs or groups of cells from the 28-cell stage to about the 400-cell stage. Two of the cells that express the gene in the >300-cell embryo may be the intestinal valve cells. Expression is seen in a discrete subset of cells in the ventral nerve cord of L1 larvae. There are three small nuclei that stain in the head region that may be G2, W, the excretory duct cell, G1 or the neuroblast that is the equipotent equivalent of the excretory cell. Staining was observed in the excretory cell.