Biology Reference
In-Depth Information
Table 1:
Regulatory genes expressed during early phases of heterocyst differentiation in
Anabaena
sp,. PCC 7120.
Gene
Gene product
Time (h) of
induction
after nitrogen-
step-down
Mutant
phenotype
No. of tsps in
the promoter
References
ntcA
(=BifA;
VF1)
(
alr4392
)
DNA-binding protein,
transcriptional activator
of CRP family; binds
to consensus sequence
-GTAN
8
TAC-
Constitutive
expression; peak
in expression
after 12 h
Het
-
;
Unable to grow
in N
2
and NO
3
-
, can
grow only on NH
4
+
Three;
-49bp,-136bp
and -180bp
Chastain
et al
. (1990),
Wei
et al.
(1993),
Ramasubramanian
et al.
(1996), Muro-Pastor
et
al.
(2002)
hetR
Master
Regulator
(
alr2329
)
DNA-binding protein
and a serine protease;
autoregulatory (HetR
from -271 tsp) and
positive feed-back
control
2 h
Het
-
; Mch-phenotype
if overexpressed
Four;
-184 bp,
-271 bp,
-696 bp
and
-728bp
Buikema & Haselkorn
(1991a,b, 2001), Black
et
al.
(1993), Huang
et
al
.
(2004)
hepA
(
hetA
)
(
alr2835
)
ATP-binding cassette
transporter; regulated
by hepK
7 h
Defective in
cohesiveness of
Heps;
Fox
-
and Fix
+
Holland and Wolk
(1990), Wolk
et al
. (1993)
patS
Peptide of 17 amino
acids; C-terminal
RGSGR sequence
required for activity
6 h
Non-expression leads
to normal pattern;
Mch-phenotype if
overexpressed
tsp located at
-314 bp
Yoon & Golden (1998,
2001)
hetC
ABC type protein
transporter;
4-6 h
Het
-
; expression
pattern resembled
that of hetR;
tsp-571
bp NtcA
activated;
tsp-293 bp
NtcA activated
but dependent
on HetR
Khudyakov & Wolk
(1997), Muro-Pastor
et
al
.
(1999, 2009)
hetF
(
all1730
)
Capsase-hemoglobinase
type protease; brings
positive auturegulation
of HetR
Het
-
; Mch-phenotype
on overexpression
Wong & Meeks (2001)*,
Wolk
et
al
. (2007), Risser
& Callahan (2008)
hetL
(
all3740
)
Possesses pentapeptide
A(D/N)LX* repeats
*represents polar amino
acid
Expression not
cell specifi c
Het
+
; Mch-phenotype
if overexpressed;
inactivation of hetR/
hetC is epistatic to
hetL overexpression
Liu & Golden (2002)
hetY
Could be an ATPase
Yoon
et al
. (2003)
hetP
6 h
Het
-
? but Mch-
phenotype on
overexpression;
Could even bypass
HetR
Five tsps.;
HetR binding
in between
-727 & -545
tsps
Fernandez-Pinas
et al
.
(1994), Higa & Callahan
(2010)
hetZ
(
alr0099
)
Het
-
;
Zhang W.
et al
. (2007)
*First described in
N
.
punctiforme
ATCC 29133 by Wong and Meeks (2001).
