Biology Reference
In-Depth Information
A
JH biosynthetic pathway
Early steps
(Mevalonate pathway)
Propionyl-CoA
Late steps
(JH biosynthesis specific pathway)
(acetyl-CoA)
Acetoacetyl-CoA thiolase (AACT)
Farnesyl diphosphate
pyrophosphatase
Acetoacetyl-CoA
Farnesol
HMG-CoA synthase (HMGS)
Farnesol dehydrogenase
HMG-CoA
Farnesal
HMG-CoA reductase (HMGR)
Farnesal dehydrogenase
Homomevalonate (Mevalonate)
Farnesoic acid
Mevalonate kinase (MevK)
Epoxidase
Phosphomevalonate
Juvenile hormone acid
Phosphomevalonate kinase (MevPK)
O-methyltransferase
(JHAMT)
Diphosphomevalonate
Diphosphomevalonate decarboxylase
(
MevPPD)
Juvenile hormone (JH)
Isopentenyl diphosphate
Dimethylallyl diphophate
Isopentenyl diphosphate
isomerase (IPPI)
C
2
H
3
C
2
H
3
O
CH
3
Farnesyl diphosphate synthase (FPPS)
O
O
Farnesyl diphosphate
JH I
B
Ecdysteroid titer
JH biosynthesis
JH titer
SP
Larval-pupal commitment
of the epidermis
01 2 3 4 0 1 2 3 4
5th
56789
4th
AACT
JHAMT
0
12 34 0
123456789
JH
biosynthesis
biosynthesis
mevalonate
enzymes
JHAMT
On
Decrease
Increase
On
Decrease
Off
Figure 3.1 The JH biosynthetic pathway and the relationship between insect hormone
titers and JH biosynthesis in Bombyx mori. (A) Diagram of the mevalonate pathway up to
FPP (early step) and the JH-specific pathway (late step). (B) Fluctuations of JH synthetic
activity by CC
-
CA and the mRNA expression of two representative JH synthetic enzymes
in the CA, and the summary for the expression levels of the JH biosynthetic enzymes
during the fourth and fifth instar stadium (
Kinjoh et al., 2007
). SP, spinneret pigmenta-
tion. Panel (A): Modified from
Bellés, Martín, & Piulachs (2005)
and
Kinjoh et al. (2007)
.
