TABLE 1.
Rescue of lin-14(lf) phenotypes by p14GFP and p14B2GFP transgenes
| Straina | No. of seam cells at L1 molt (n)b | % adult alae at L3 molt (n)c | % VPC divisions at L2 molt (n)d | % egl(−) adults (n)e | No. of intestinal cells at L2 molt (n)f | % Alae formation at L4 molt (n)g |
|---|---|---|---|---|---|---|
| Wild type | 6.0 ± 0.0 (20) | 0.0 (585) | 0.0 (69) | 0.0 (100) | 33.2 ± 1.3 (21) | 0.0 (455) |
| lin-14(ma135) | 11.2 ± 0.9 (15) | 100.0 (312) | 100.0 (45) | 100.0 (100) | 19.7 ± 0.6 (17) | NA |
| lin-14(n179ts) @ 25°C | 10.5 ± 0.8 (11) | 99.6 (770) | 54.4 (57) | 100.0 (110) | 20.2 ± 1.4 (19) | NA |
| VT886 (ma135; maEx167) | 6.0 ± 0.0 (10) | 8.3 (325) | 12.4 (57) | 7.5 (120) | 29.0 ± 3.4 (19) | 0.4 (260) |
| VT887 @25°C (n179; maEx168) | 6.2 ± 0.4 (12) | 2.0 (546) | 0.0 (36) | 13.6 (110) | 30.0 ± 2.4 (12) | 1.3 (234) |
| VT888 (ma135; maEx168) | 6.0 ± 0.0 (15) | 0.3 (338) | 3.3 (60) | 11.7 (120) | 31.1 ± 2.2 (21) | 6.8 (585) |
Transgenic animals were identified by their GFP fluorescence.
In lin-14(lf) mutant animals, lateral hypodermal V cells in the L1 stage express an L2-specific division pattern in place of the L1-specific division pattern and consequently will contain up to 12 seam cells at each side of the animal, instead of six, by the end of the L1 stage. Rescue of this L1 phenotype was measured here by the number of seam cells at the L1 molt on one side of the animal ± standard error of the mean. n, number of animals scored.
lin-14(lf) animals undergo only three larval molts and synthesize adult cuticle precociously at the third molt. The adult alae scored here are a cuticle structure that is specifically made by seam cells during their synthesis of adult cuticle (2). n, total number of seam cells scored.
In lin-14(lf) hermaphrodites, VPCs P5.p, P6.p, and P7.p divide and produce vulva cells one stage earlier than normal, at the L2 instead of the L3 stage. n, total number of VPCs from among P5.p, P6.p, and P7.p that were scored for precocious divisions at the L2 molt.
The precocious vulva development contributes to the egg-laying defects [egl(−)] in lin-14(lf) adults. To score the egl(−) phenotype, late L4 animals were picked onto one plate, and 24 to 48 h later, the number of egl(−) animals were counted by their “egg-bag” phenotype. n, total number of animals.
lin-14 activity is required for intestinal cells to execute a round of divisions in the late L1 stage (30). In the wild type, many of the 20 intestinal nuclei divide at the end of the L1 stage, resulting in a final complement of approximately 33 total intestinal nuclei (31). In lin-14(ma135) animals and in lin-14(n179ts) animals at 25°C, none of the intestinal nuclei divides and the total number of nuclei after the L1 stage remains at 20. n, total number of animals scored. Data are means ± standard errors of the mean.
Overexpression of LIN-14 late in development leads to retarded larval fates, including the production of larval cuticle instead of adult cuticle at the L4 molt, revealed by the absence of adult-specific lateral alae. n, number of seam cells scored for the production of adult lateral alae at the L4 molt.