Biology Reference
In-Depth Information
Primordial
hermaphroditic
gonad
Sox3,
Aromatase
High
E
2
level
Ovary
Sox3, p450 aromA,FTZ-F1
Dm
rt1,sox9,
TS
H
High T level
T
E
S
T
I
S
Fig. 44.
A hypothetic model of genetic and endocrine mechanisms of protogynous sex change
in hermaphroditic groupers. ← = inhibition, → = activation
like
G. aculeatus sox9b, O. latipes sox9b
and
D. rerio sox 9b
as well as
protogynous hermaphrodites
E. coioides sox9
and
M. albus sox9a1.
The
cluster 2 includes
D. rerio sox9a, G. aculeatus sox9a, O. latipes sox9a
and
Monopterus albus sox9a
(Luo et al., 2010). Clearly, both gonochoristic
and hermaphroditic fi shes employ the same sex differentiation genes.
sox9
is a sex related transcription factor and the earliest known marker
of Sertoli cell differentiation. Over-expression of
sox9
causes male
sexual development in an XX individual (Gardner et al., 2003).
In
E. coioides
sox3
expression is detected very early in the nuclei of
some PGCs along germinal epithelium.
Ecsox3-
positive PGCs develop
toward spermatogonia. But on cessation of
Ecsox3
expression, the
expressed
Ecsox3
are concentrated in one or two signal spots and
are located outside the nuclei.
Ecsox3
transcripts begin to express at
the lowest, as detected from MT-treated sex reversing grouper. The
interesting data of Yao et al. (2007) indicate that as the transcription
factor,
Ecsox3
has a more important role in oogenesis than
spermatogenesis.
sox5
is involved in expressing Ikappaβ, a protein