Table 2

Hypomorphic RNAi phenotypes produced by titration of IPTG concentration



Concentration of IPTG



Test gene
Experimental phenotype
0
1 pM
1 nM
1 µM
1 mM
10 mM

unc-37
Emb
0%
4%
11%
48%
100%
77%

Unc
0%
10%
10%
100%
NA
69%
hlh-2
Emb
0%
8%
20%
97%
100%
86%

Unc
0%
13%
9%
100%
NA
100%
mei-1
Emb
0%
7%
16%
71%
100%
71%

Male
0%
0%
6%
8%
NA
3%
rba-2
Emb
56%
100%
100%
100%
100%
100%

Four genes were tested to determine whether reducing the concentration of IPTG used to induce the bacteria could elicit hypomorphic phenotypes from worms escaping embryonic lethality. The percentage of embryonic lethality (Emb) was determined from the total number of progeny, whereas the percentage of uncoordinated (Unc) or male worms was determined from escapers only. High concentrations of IPTG (for example 10 mM) overinduce and presumably kill the bacteria, thus leading to a lower penetrance of strong phenotypes. Data shown represent the progeny of three fed worms. NA, not applicable.

Kamath et al. Genome Biology 2000 2:research0002.1   doi:10.1186/gb-2000-2-1-research0002