Steroid Regulation of C. elegans Diapause, Developmental Timing, and Longevity - Current Topics in Developmental Biology - page 183

A

Environmental input

TGF- β
Insulin

Favorable Unfavorable

Daf-9
CYP

DA

DA

DIN-1
CoR

DA

DAF-12
NHR

DAF-12
NHR

LIN-42

let-7 s/miR let-7 s/miR

hbl-1
L2 programs
or arrest

hbl-1
L2 programs
or dauer arrest

L3 programs
or progression

L3 programs
or progression

Reproduction, short life Dauer diapause, long life

B

Worms Insects Mammals

cGMP

PTTH GnT

TGF- β TGF- β TGF- β

Ins/IGF Ins/IGF Ins/IGF

DAF-9/CYP DAF-9/CYP

DA

DAF-9/CYP
Ecd

CYP450 CYP450

DAF-9/CYP
E

DA

Ecd E

DA Ecd E

DAF-12 let-7 EcR let-7 ER let-7?

Reproduction/Dauer Metamorphosis Puberty

Figure 7.1 A. Model for regulation of dauer and reproduction development. C. elegans
dauer signaling pathways work as a molecular switch (see text). In favorable conditions,
TGF-b and IIS positively affect production of the DAs. DA binds to DAF-12 activating
its transcriptional activity, and DA production is amplified through feedback on daf-9
(Continued)