BIOL 142 Lecture Notes - Lecture 23: Replica Plating, Microrna, Gene Expression
30 Apr 2018
School
Department
Course
Professor
!"#$%&%'()*+",-&."/
Explain(the(general(mechanisms(of(gene(regulation.(
1.
Describe(the(role(of(lactose(in(the(induction(of(β-Galactosidase(in(E.(coli.(
2.
Design(an(experiment(using(indicator(plates(coated(with(X-Gal(to(assay(β-
Galactosidase(activity.(
3.
Explain(how(replica(plating(was(used(in(a(genetic(screen(to(identify(the(lacZ,(
lacY,(and(lacI(genes.
4.
1.(A(cell(does(not(express(all(of(its(genes(all(of(the(time.(
0"%"("12$"//&3%(3,,4$/(56"%(#('"%"(2$374,-(&/(#,-&."89(*"&%'(/9%-6"/&:"7(#%7(
4/"7(&%(#(,"88;(<"'48#-&3%(3=('"%"("12$"//&3%(&/(,$&-&,#8(-3(-6"("==&,&"%-(4/"(3=(
$"/34$,"/(#%7(-64/(/4$.&.#8;(
>
?"88/(#$"(."$9(/"8",-&."(#*34-(-6"('"%"/(-6"9("12$"//@(635(/-$3%'89(-6"9(#$"(
"12$"//"7@(#%7(56"%(-6"9(#$"("12$"//"7;(
>
0"%"/(,#%(*"(4%7"$(-$#%/,$&2-&3%#8@(-$#%/8#-&3%#8@(3$(23/-A-$#%/8#-&3%#8(,3%-$38
>
B12$"//&%'(-6"C(#88(-6"(-&C"(
D3487(*"("%"$'"-&,#889( 4%=#.3$#*8"
○
D3487%E-(6#."(/2",&=&,(,"88( -92"/
F""7(-3(C#G"(7&/-&%,-(-&//4"/(#%7(3$'#%/
§
○
>
Transcriptional,control 3,,4$/(56"%(-6"(,"88(73"/(%3-(2$374,"(C<FH;(
I6"(,"88( #.3&7/(-6"(2$374,-&3%(3=(-6"/"('"%"/(*9(4-&8&:&%'($"'48#-3$9(2$3-"&%/(
-6#-(2$"."%-(<FH(2389C"$#/"(=$3C(*&%7&%'(-3(#(2$3C3-"$
>
D6#-(934(%""7(-3(C#G"(#%(C<FH
>
<"'48#-"(&=($"'48#-3$9(2$3-"&%/(#$"(#,-&."(3$("."%(C#7"
>
Translational,control #8835/(-6"(,"88( -3(2$"."%-(-6"(-$#%/8#-&3%(3=(#%(C<FH(C38",48"(
-6#-(6#/(#8$"#79(*""%(-$#%/,$&*"7;(
I6&/(,#%(3,,4$(-6$34'6(C#%9(C",6#%&/C/>
<"'48#-3$9(C38",48"/(,#%(/2""7(42(C<FH(7"'$#7#-&3%;>
I$#%/8#-&3%(&%&-&#-&3%(,#%(*"(#8-"$"7>
I$#%/8#-&3%(2$3-"&%/(,#%(*"(#==",-"7;>
miRNAJ(/63$-(%4,8"&,(#,&7(/-$"-,6"/(-6#-(#$"(,3C28"C"%-#$9(-3(-#$'"-(<FH/K(#,-(
-6$34'6(,3C28"C"%-#$9(*#/"(2#&$&%'(5&-6(-6"(C<FH(-3(7"'$#7"(C<FH
F#-4$#8(2$3,"//(3=($"'48#-&%'(C<FH(8&="/2#%
○
?#%(&%+",-(#$-&=&,( C&<FH(&%(-6"(8#*(-3(,#4/"(RNA,silencingJ(#77(#$-&=&,(
<FH(-3(735%$"'48#-"(#('"%"
○
>
Post-translational ,3%-$38(3,,4$/(56"%(-6"(,"88(=#&8/(-3(#,-&.#-"(#(C#%4=#,-4$"7(
2$3-"&%(*9(,6"C&,#8(C37&=&,#-&3%
0$""%(/6#2"J(2$3-"&%(5&-6(-"$-&#$9(/6#2">
LJ(263/26#-"('$342(%"'#-&."89(,6#$'"7
H77&%'(&-(,6#%'"/(2$3-"&%/(/6#2"(#%7(-6"$"=3$"(=4%,-&3%
○
Phosphorylate 2$3-"&%(-3J
Activate 2$3-"&%(*9($"."#8&%'(#%(#,-&."(/&-"
§
Inhibit 2$3-"&%(*9(6&7&%'(#,-&."(/&-"
§
○
>
1. D6&,6(3=(-6"(=38835&%'(8"."8/(3=('"%"("12$"//&3%($"'48#-&3%(#8835/(-6"(C3/-(
"==&,&"%-(M&;";AAC3/-("%"$'"-&,#889(=#.3$#*8"N($"/23%/"(-3("%.&$3%C"%-#8(,6#%'"O(
transcriptional,control,A.
-$#%/8#-&3%#8(,3%-$38(P;
23/-A-$#%/8#-&3%#8(,3%-$38(?;
2. D6&,6(3=(-6"(=38835&%'(8"."8/(3=('"%"("12$"//&3%($"'48#-&3%(#8835/(-6"(C3/-($#2&7(
$"/23%/"(-3("%.&$3%C"%-#8(,6#%'"O(
-$#%/,$&2-&3%#8(,3%-$38(H;
-$#%/8#-&3%#8(,3%-$38(P;
post-translational,controlC.
H88(-6$""(=3$C/(3=('"%"("12$"//&3%(,3%-$38(3,,4$(&%(*#,-"$&#
I$#%/,$&2-&3%#8(,3%-$38(&/(/835(*4-("==&,&"%-
Q3/-("%"$'"-&,#889(=#.3$#*8"
○
R3%E-(C#G"(C<FH
○
>
I$#%/8#-&3%#8(,3%-$38(#8835/(#(,"88(-3(S4&,G89(,6#%'"(56&,6(2$3-"&%/(#$"(
2$374,"7
Q#G&%'(C&<FH/(-3(/&8"%-(C<FH/(&/(%3-(-6"(C3/-("%"$'"-&,#889(=#.3$#*8"(3$(
"==&,&"%-(C"-637(-3(/64-(735%(#('"%"(M4/"(-$#%/,$&2-&3%#8N
○
>
L3/-A-$#%/8#-&3%#8(,3%-$38(2$3.&7"/(-6"(C3/-($#2&7($"/23%/"(*4-(&/("%"$'"-&,#889(
"12"%/&."
P"/-(=3$("%.&$3%C"%-#8(,6#%'"
○
T=(934(+4/-(/-32(-$#%/,$&2-&3%@(934(#8$"#79(6#."(=4%,-&3%#8(2$3-"&%(&%(-6"(
,"88( -6#-(5&88(G""2(53$G&%'("."%(934(&=(934(73%E-(C#G"(#%9(C3$"(C<FH/(
M569(-6"9(73%E-(4/"(-$#%/,$&2-&3%#8N
L$3-"&%(53487(*"(7"'$#7"7@(*4-(%3-(#/(S4&,G89(#/(&=(934(-4$%"7(3==(
-6"(2$3-"&%/
§
○
>
2.(Lactose(induces(β-Galactosidase(expression(in(E.(coli.
!#,-3/"(U(V('84,3/"(W(V('#8#,-3/">
B;(,38&(%""7/(#%("%:9C"(-3(*$"#G(42(-6"(*3%7(3=('84,3/"(#%7('#8#,-3/">
B;(,38&(2$374,"/(6&'6(8"."8/(3= β-galactosidase MXA'#8N(3%89(56"%(8#,-3/"(&/(
2$"/"%-(&%(-6"("%.&$3%C"%-
>
I64/@(8#,-3/"(#,-/(#/(#%(inducerJ(#(C38",48"(-6#-(/-&C48#-"/(-6"("12$"//&3%(3=(#(
/2",&=&,('"%"
>
I6"(8"."8( 3=("12$"//&3%(3=(7&=="$"%-('"%"/(,#%(*"(6&'689(.#$&#*8"Y-6&/(#8835/(,"88/(-3(
$"/23%7(-3("%.&$3%C"%-#8(,6#%'"/
B;(,38&Z/(2$"="$$"7(,#$*3%(/34$,"(&/('84,3/"(=3$('89,389/&/>
P"=3$"(&-(,#%(4-&8&:"(8#,-3/"@(B;(,38&(C4/-(-$#%/23$-(&-(&%-3(-6"(,"88@(56"$"(-6"(
"%:9C"(XA'#8#,-3/&7#/"(,#%(,8"#."(&-(-3(2$374,"('84,3/"(#%7('#8#,-3/"
>
3.(X-Gal(is(a(dye(used(to(detect(β-Galactosidase(activity
I3(G%35(56&,6(,"88/(#$"(,$"#-&%'(-6"("%:9C"
H//"//(56"-6"$(-6"(/2",&=&,("%:9C"(&/(3$(&/%E-("12$"//"7(*([A0#8(-338
○
>
[A'#8(833G/(G&%7(3=(8&G"(8#,-3/"
D6"%(934(,4-(-6"('89,3/&7&,(8&%G#'"@(934(=$""(42(-6"([(C38",48"/(-6#-(#$"(
,383$8"//
○
T%(-6"(,4-(=3$C@(-6"9(2$",&2&-#-"(#%7(*",3C"(*84"
○
>
I6"(,383$8"//(79"([A0#8(&/(#(7&C"$(,3C23/"7(3=(#([(M\A*$3C3A ]A,683$3A^A&%73898(
C3%3C"$N(#%7(0#8#,-3/";(
[(&/(,383$8"//
○
>
XA0#8#,-3/&7#/"(,8"#."/(-6"(8&%G#'"(*"-5""%(-6"(\A*$3C3A]A ,683$3A^A&%73898(
C3%3C"$(#%7(0#8#,-3/";(
?4-(7&C"$(&%-3('84,3/"(#%7('#8#,-3/"(-3(#8835(-6"(C38",48"/(-3(7&C"$A&:"
○
>
I6"(7&C"$&:#-&3%(3=(\A*$3C3A]A ,683$3A^A&%73898(C3%3C"$/($"/48-/(&%(-6"(
=3$C#-&3%(3=(#(*84"(2$",&2&-#-";
L$",&2&-#-"(&/([[
○
>
T%7&,#-3$(28#-"/(,3#-"7(5&-6([A0#8(,#%(*"(4/"7(-3(7"-",-(XA0#8#,-3/&7#/"(#,-&.&-9
?"88/("12$"//&%'("%:9C"(#$"(*84">
3. T%(!"#$%&%'?#-#89-&,/@(7"/&'%(#%("12"$&C"%-(4/&%'(&%7&,#-3$(28#-"/(-3(-"/-(&=(B;(,38&(
2$374,"(XA0#8#,-3/&7#/"(56"%(*3-6('84,3/"(#%7(8#,-3/"(#$"(2$"/"%-;
L8#-"/J
L8#-"(VJ('84,3/"(3%89 M,3%-$38N
D&88(*"(56&-"(,383%&"/
§
D&88(%3-(*"(#*8"(-3(,4-([A'#8(79"(-3(C#G"(2$",&2&-#-"
§
○
L8#-"(_J(8#,-3/"(3%89 M,3%-$38N
D&88(*"(*84"
§
F""7(-3(C#G"(PA0#8(&%(3$7"$(-3(,4-(-6"(8#,-3/"
§
○
L8#-"(^J(*3-6('84,3/"(#%7(8#,-3/" M"12"$&C"%-#8N
D&88(*"(56&-"
§
In(the(presence(of(glucose,(these(cells(do(not(produce(B-Gal(because(
they(have(glucose
§
B-Gal(gene(stays(silent
§
○
>
T=(-6"("%:9C"(&/("12$"//"7@(5&88(*"(*84"(3%(28#-">
`635/(-6"(235"$(3=(-6"(PA0#8(-338(#%7(>
Shows,the,effect,of,environmental,conditions,on,a,specific,gene>
4.(To(identify(the(required(genes(for(lactose(metabolism,(Monod(and(François(Jacob(
isolated(E.(coli(mutants(that(could(not(metabolize(lactose.
Genetic,screeningJ(#22$3#,6(-3('"%3C"(/-479(56"$"(934($#%73C89(*$"#G('"%"/(
#%7(833G(=3$(26"%3-92"(3=(&%-"$"/-
>
T/38#-&%'(C4-#%-/(5&-6($"/2",-(-3(#(2#$-&,48#$(-$#&-(&/(#(-53A/-"2(2$3,"//;
0"%"$#-"(#(8#$'"(%4C*"$(3=(&%7&.&74#8/(5&-6(C4-#-&3%/(#-($#%73C(
83,#-&3%/(&%(-6"&$('"%3C"/;
`-#$-(5&-6(C4-#'"%&:&%'(/-"2(
§
?$"#-&%'($#%73C(,6#%'"/(&%(-6"('"%3C"(3=(-6"/"(3$'#%&/C/(
§
V;
a/"(genetic,screening 3%(-6"(C4-#%-/(-3(=&%7(&%7&.&74#8/(5&-6(7"=",-/(&%(
-6"(2$3,"//(3$(2#-65#9(&%(S4"/-&3%;(T%(-6&/(#22$3#,6@(5"(5&88(4/"(replica,
plating.
!33G(#-(26"%3-92"(#%7(/""(&=(#%9(3=(-6"(C4-#%-/(6#."(#(26"%3-92"(
,3%/&/-"%-(5&-6(#$"#(3=(/-479
§
_;
>
b35(-3(C4-#'"%&:"J
BQ`
○
ac(8&'6-
○
[A$#9/(Y?#%(73(,6$3C3/3C#8(,6#%'"@(56&,6(#==",-/(#(83-;(0"%"$#889(%3-(
4/"7;
○
>
Transposable,elements/mobile,DNA,elementsJ(#(/"S4"%,"(3=(RFH(-6#-(6#/(
2#$-&,48#$(RFH(/"S4"%,"/(3%("&-6"$("%7(-6#-(#8835(&-(-3(*"(,4-(34-(3=(3%"(
83,#-&3%(&%(-6"('"%3C"(#%7(&%/"$-"7(&%(#%3-6"$($#%73C(28#,"(&%(-6"('"%3C"
?3487(*$"#G(-6"('"%"(&=(&%/"$-"7(&%(-6"(C&778"(3=(#('"%"
○
H(5#9(-3(73(/-"2(V(3=('"%"-&,(/,$""%&%'
○
>
<"28&,#(28#-&%'
a/&%'($"28&,#(28#-&%'(-3('$35(,"88/(4%7"$(#(=#.3$#*8"(,3%7&-&3%(3=('$35-6>
L4-(."8."-(*83,G(3%(-32(-3(2&,G(42(/3C"(,"88/(=$3C("#,6(,383%9>
a/"(-6"(*83,G(-3(28#,"(/3C"(,"88/(3%(#%3-6"$(28#-"(-6#-(,#%(6#."(#(7&=="$"%-(
,3C23%"%-
>
?329&%'(,"88/(3%(7&=="$"%-(28#-"/(3=(7&=="$"%-(,3C23%"%-/>
I6"($"28&,#( 28#-&%'(#22$3#,6(-3(&7"%-&=9(C4-#%-(,"88/
0$35(C4-#%-(*#,-"$(,383%&"/(3%(C#/-"$(28#-"/(,3%-#&%&%'(#(C"7&4C(5&-6(
'84,3/"
Q4-#%-/(/63487('$35(3%('84,3/"@(73%E-(%""7(#%9-6&%'(5&-6(PA0#8
○
H;
I$#%/="$(,"88/(=$3C("#,6(,383%9(-3(#(2&","(3=(/-"$&8&:"7(."8."-;
L&,G(42(,383%&"/(-3(C3."(-3(#%3-6"$(28#-"
○
P;
I$#%/="$(,"88/(-3(#(28#-"(5&-6(#(C"7&4C(,3%-#&%&%'(3%89(8#,-3/"(d-6&/(%"5(28#-"(
&/(,#88"7( #($"28&,#(28#-"
Q3/-(3=(-6"(-&C"@(5&88('$35(3%(8#,-3/"
○
D6"%(,$"#-&%'($#%73C(C4-#-&3%/@(4/4#889(73%E-(6&-(56#-(934(5#%-(-3(
/-479
○
?;
?3C2#$"(-6"(,383%&"/(3%(-6"(C#/-"$(28#-"(#%7($"28&,#(28#-"
e%35(56#-(,383%&"/(/63487('$35(3%("#,6(28#-"
○
T=(-6"$"(#$"(_f(,383%&"/(3%('84,3/"(#%7(Vg(3%(8#,-3/"@(934(,#%(=&%7(934$(
C4-#%-
○
R;
4;(L$"7&,-(56"-6"$(#(*#,-"$(,383%9(5&-6(#(C4-#-&3%(&%(#($"S4&$"7('"%"(=3$(8#,-3/"(
C"-#*38&/C(5&88('$35(3%J
H%(#'#$(28#-"(,3%-#&%&%'(3%89('84,3/";
YesA.
R3%E-(6#."(#%9-6&%'(-3(73(5&-6('84,3/"(C"-#*38&/C
○
F3P;
T;
H%(#'#$(28#-"(,3%-#&%&%'(3%89(8#,-3/";
h"/H;
NoB.
T=(934E."(7&/$42-"7(&-/(#*&8&-9(-3(4/"(8#,-3/"(#/(#%("%"$'9(/34$,"
○
TT;
I6"(-6$""(B;(,38&('"%"/(&%.38."7(&%(8#,-3/"(C"-#*38&/C(5"$"(%#C"7(8#,i@(8#,h@(#%7(8#,T
8#,iAC4-#%-/(8#,G(=4%,-&3%#8(B-gal>
8#,hAC4-#%-/(8#,G(-6"(C"C*$#%"(2$3-"&% galactoside,permease #%7(/3(,#%%3-(
-$#%/23$-(8#,-3/"(&%-3(-6"(,"88
I3('"-(697$326&8&,(/4*/-#%,"(#,$3//(28#/C#(C"C*$#%"@(%""7(-3(C#G"(&-(
2"$C"#*8"(-3(-6"(,#$*3697$#-"(
○
>
8#,TAC4-#%-/(#$"(,#88"7(constitutive,mutants *",#4/"(-6"9(2$374,"(XA
'#8#,-3/&7#/"(#%7('#8#,-3/&7"(2"$C"#/"("."%(56"%(8#,-3/"(&/(#*/"%-;
Constitutive,mutantsJ(-4$%('"%"/(3%
○
D&88("12$"//(&-($"'#$78"//(3=(/4'#$(2$"/"%-
○
>
I6"(A*9(-6"('"%"(C"#%/(%488(C4-#-&3%>
I6"(8#,i(#%7(8#,h('"%"/(,37"(=3$(2$3-"&%/(&%.38."7(&%(8#,-3/"(C"-#*38&/C@(56&8"(-6"(
8#,T('"%"(2$374,-(/"$."/(#($"'48#-3$9(=4%,-&3%;
D6"%(934(*$"#G(-6"($"2$"//3$(8#,T(-6"%(735%/-$"#C(2$3-"&%/(#$"(#85#9/(*"&%'(
8#7"(&%(-6"(,"88
>
T%(-6"(#*/"%,"(3=(8#,-3/"@(-6"(8#,T('"%"(2$374,-(/64-/(735%("12$"//&3%(3=(8#,i(
#%7(8#,h;(D6"%(8#,-3/"(&/(2$"/"%-@(635"."$@(-$#%/,$&2-&3%(3=(8#,i(#%7(8#,h(&/(
&%74,"7;
>
j4$-6"$(/-47&"/($"."#8"7(-6#-(-6"(8#,i@(8#,h@(#%7(8#,T('"%"/(#$"(83,#-"7(,83/"(
-3'"-6"$(3%(-6"(,&$,48#$(B;(,38&(,6$3C3/3C";(I6&/(/4''"/-"7(-6#-(8#,T(,3487(
,3%-$38(*3-6(8#,i(#%7(8#,h;
>
Prokaryotic*Gene*Regulation*I
D"7%"/7#9@( H2$&8(VV@(_fVk
VVJ\k(HQ
!"#$%&%'()*+",-&."/
Explain(the(general(mechanisms(of(gene(regulation.(1.
Describe(the(role(of(lactose(in(the(induction(of(β-Galactosidase(in(E.(coli.(2.
Design(an(experiment(using(indicator(plates(coated(with(X-Gal(to(assay(β-
Galactosidase(activity.(
3.
Explain(how(replica(plating(was(used(in(a(genetic(screen(to(identify(the(lacZ,(
lacY,(and(lacI(genes.
4.
1.(A(cell(does(not(express(all(of(its(genes(all(of(the(time.(
0"%"("12$"//&3%(3,,4$/(56"%(#('"%"(2$374,-(&/(#,-&."89(*"&%'(/9%-6"/&:"7(#%7(
4/"7(&%(#(,"88;(<"'48#-&3%(3=('"%"("12$"//&3%(&/(,$&-&,#8(-3(-6"("==&,&"%-(4/"(3=(
$"/34$,"/(#%7(-64/(/4$.&.#8;(
>
?"88/(#$"(."$9(/"8",-&."(#*34-(-6"('"%"/(-6"9("12$"//@(635(/-$3%'89(-6"9(#$"(
"12$"//"7@(#%7(56"%(-6"9(#$"("12$"//"7;(
>
0"%"/(,#%(*"(4%7"$(-$#%/,$&2-&3%#8@(-$#%/8#-&3%#8@(3$(23/-A-$#%/8#-&3%#8(,3%-$38>
B12$"//&%'(-6"C(#88(-6"(-&C"(
D3487(*"("%"$'"-&,#889( 4%=#.3$#*8"
○
D3487%E-(6#."(/2",&=&,(,"88( -92"/
F""7(-3(C#G"(7&/-&%,-(-&//4"/(#%7(3$'#%/
§
○
>
Transcriptional,control 3,,4$/(56"%(-6"(,"88(73"/(%3-(2$374,"(C<FH;(
I6"(,"88( #.3&7/(-6"(2$374,-&3%(3=(-6"/"('"%"/(*9(4-&8&:&%'($"'48#-3$9(2$3-"&%/(
-6#-(2$"."%-(<FH(2389C"$#/"(=$3C(*&%7&%'(-3(#(2$3C3-"$
>
D6#-(934(%""7(-3(C#G"(#%(C<FH>
<"'48#-"(&=($"'48#-3$9(2$3-"&%/(#$"(#,-&."(3$("."%(C#7">
Translational,control #8835/(-6"(,"88( -3(2$"."%-(-6"(-$#%/8#-&3%(3=(#%(C<FH(C38",48"(
-6#-(6#/(#8$"#79(*""%(-$#%/,$&*"7;(
I6&/(,#%(3,,4$(-6$34'6(C#%9(C",6#%&/C/
>
<"'48#-3$9(C38",48"/(,#%(/2""7(42(C<FH(7"'$#7#-&3%;
>
I$#%/8#-&3%(&%&-&#-&3%(,#%(*"(#8-"$"7
>
I$#%/8#-&3%(2$3-"&%/(,#%(*"(#==",-"7;
>
miRNAJ(/63$-(%4,8"&,(#,&7(/-$"-,6"/(-6#-(#$"(,3C28"C"%-#$9(-3(-#$'"-(<FH/K(#,-(
-6$34'6(,3C28"C"%-#$9(*#/"(2#&$&%'(5&-6(-6"(C<FH(-3(7"'$#7"(C<FH
F#-4$#8(2$3,"//(3=($"'48#-&%'(C<FH(8&="/2#%
○
?#%(&%+",-(#$-&=&,( C&<FH(&%(-6"(8#*(-3(,#4/"(RNA,silencingJ(#77(#$-&=&,(
<FH(-3(735%$"'48#-"(#('"%"
○
>
Post-translational ,3%-$38(3,,4$/(56"%(-6"(,"88(=#&8/(-3(#,-&.#-"(#(C#%4=#,-4$"7(
2$3-"&%(*9(,6"C&,#8(C37&=&,#-&3%
0$""%(/6#2"J(2$3-"&%(5&-6(-"$-&#$9(/6#2"
>
LJ(263/26#-"('$342(%"'#-&."89(,6#$'"7
H77&%'(&-(,6#%'"/(2$3-"&%/(/6#2"(#%7(-6"$"=3$"(=4%,-&3%
○
Phosphorylate 2$3-"&%(-3J
Activate 2$3-"&%(*9($"."#8&%'(#%(#,-&."(/&-"
§
Inhibit 2$3-"&%(*9(6&7&%'(#,-&."(/&-"
§
○
>
1. D6&,6(3=(-6"(=38835&%'(8"."8/(3=('"%"("12$"//&3%($"'48#-&3%(#8835/(-6"(C3/-(
"==&,&"%-(M&;";AAC3/-("%"$'"-&,#889(=#.3$#*8"N($"/23%/"(-3("%.&$3%C"%-#8(,6#%'"O(
transcriptional,control,A.
-$#%/8#-&3%#8(,3%-$38(P;
23/-A-$#%/8#-&3%#8(,3%-$38(?;
2. D6&,6(3=(-6"(=38835&%'(8"."8/(3=('"%"("12$"//&3%($"'48#-&3%(#8835/(-6"(C3/-($#2&7(
$"/23%/"(-3("%.&$3%C"%-#8(,6#%'"O(
-$#%/,$&2-&3%#8(,3%-$38(H;
-$#%/8#-&3%#8(,3%-$38(P;
post-translational,controlC.
H88(-6$""(=3$C/(3=('"%"("12$"//&3%(,3%-$38(3,,4$(&%(*#,-"$&#
I$#%/,$&2-&3%#8(,3%-$38(&/(/835(*4-("==&,&"%-
Q3/-("%"$'"-&,#889(=#.3$#*8"
○
R3%E-(C#G"(C<FH
○
>
I$#%/8#-&3%#8(,3%-$38(#8835/(#(,"88(-3(S4&,G89(,6#%'"(56&,6(2$3-"&%/(#$"(
2$374,"7
Q#G&%'(C&<FH/(-3(/&8"%-(C<FH/(&/(%3-(-6"(C3/-("%"$'"-&,#889(=#.3$#*8"(3$(
"==&,&"%-(C"-637(-3(/64-(735%(#('"%"(M4/"(-$#%/,$&2-&3%#8N
○
>
L3/-A-$#%/8#-&3%#8(,3%-$38(2$3.&7"/(-6"(C3/-($#2&7($"/23%/"(*4-(&/("%"$'"-&,#889(
"12"%/&."
P"/-(=3$("%.&$3%C"%-#8(,6#%'"
○
T=(934(+4/-(/-32(-$#%/,$&2-&3%@(934(#8$"#79(6#."(=4%,-&3%#8(2$3-"&%(&%(-6"(
,"88( -6#-(5&88(G""2(53$G&%'("."%(934(&=(934(73%E-(C#G"(#%9(C3$"(C<FH/(
M569(-6"9(73%E-(4/"(-$#%/,$&2-&3%#8N
L$3-"&%(53487(*"(7"'$#7"7@(*4-(%3-(#/(S4&,G89(#/(&=(934(-4$%"7(3==(
-6"(2$3-"&%/
§
○
>
2.(Lactose(induces(β-Galactosidase(expression(in(E.(coli.
!#,-3/"(U(V('84,3/"(W(V('#8#,-3/">
B;(,38&(%""7/(#%("%:9C"(-3(*$"#G(42(-6"(*3%7(3=('84,3/"(#%7('#8#,-3/">
B;(,38&(2$374,"/(6&'6(8"."8/(3= β-galactosidase MXA'#8N(3%89(56"%(8#,-3/"(&/(
2$"/"%-(&%(-6"("%.&$3%C"%-
>
I64/@(8#,-3/"(#,-/(#/(#%(inducerJ(#(C38",48"(-6#-(/-&C48#-"/(-6"("12$"//&3%(3=(#(
/2",&=&,('"%"
>
I6"(8"."8( 3=("12$"//&3%(3=(7&=="$"%-('"%"/(,#%(*"(6&'689(.#$&#*8"Y-6&/(#8835/(,"88/(-3(
$"/23%7(-3("%.&$3%C"%-#8(,6#%'"/
B;(,38&Z/(2$"="$$"7(,#$*3%(/34$,"(&/('84,3/"(=3$('89,389/&/>
P"=3$"(&-(,#%(4-&8&:"(8#,-3/"@(B;(,38&(C4/-(-$#%/23$-(&-(&%-3(-6"(,"88@(56"$"(-6"(
"%:9C"(XA'#8#,-3/&7#/"(,#%(,8"#."(&-(-3(2$374,"('84,3/"(#%7('#8#,-3/"
>
3.(X-Gal(is(a(dye(used(to(detect(β-Galactosidase(activity
I3(G%35(56&,6(,"88/(#$"(,$"#-&%'(-6"("%:9C"
H//"//(56"-6"$(-6"(/2",&=&,("%:9C"(&/(3$(&/%E-("12$"//"7(*([A0#8(-338
○
>
[A'#8(833G/(G&%7(3=(8&G"(8#,-3/"
D6"%(934(,4-(-6"('89,3/&7&,(8&%G#'"@(934(=$""(42(-6"([(C38",48"/(-6#-(#$"(
,383$8"//
○
T%(-6"(,4-(=3$C@(-6"9(2$",&2&-#-"(#%7(*",3C"(*84"
○
>
I6"(,383$8"//(79"([A0#8(&/(#(7&C"$(,3C23/"7(3=(#([(M\A*$3C3A ]A,683$3A^A&%73898(
C3%3C"$N(#%7(0#8#,-3/";(
[(&/(,383$8"//
○
>
XA0#8#,-3/&7#/"(,8"#."/(-6"(8&%G#'"(*"-5""%(-6"(\A*$3C3A]A ,683$3A^A&%73898(
C3%3C"$(#%7(0#8#,-3/";(
?4-(7&C"$(&%-3('84,3/"(#%7('#8#,-3/"(-3(#8835(-6"(C38",48"/(-3(7&C"$A&:"
○
>
I6"(7&C"$&:#-&3%(3=(\A*$3C3A]A ,683$3A^A&%73898(C3%3C"$/($"/48-/(&%(-6"(
=3$C#-&3%(3=(#(*84"(2$",&2&-#-";
L$",&2&-#-"(&/([[
○
>
T%7&,#-3$(28#-"/(,3#-"7(5&-6([A0#8(,#%(*"(4/"7(-3(7"-",-(XA0#8#,-3/&7#/"(#,-&.&-9
?"88/("12$"//&%'("%:9C"(#$"(*84">
3. T%(!"#$%&%'?#-#89-&,/@(7"/&'%(#%("12"$&C"%-(4/&%'(&%7&,#-3$(28#-"/(-3(-"/-(&=(B;(,38&(
2$374,"(XA0#8#,-3/&7#/"(56"%(*3-6('84,3/"(#%7(8#,-3/"(#$"(2$"/"%-;
L8#-"/J
L8#-"(VJ('84,3/"(3%89 M,3%-$38N
D&88(*"(56&-"(,383%&"/
§
D&88(%3-(*"(#*8"(-3(,4-([A'#8(79"(-3(C#G"(2$",&2&-#-"
§
○
L8#-"(_J(8#,-3/"(3%89 M,3%-$38N
D&88(*"(*84"
§
F""7(-3(C#G"(PA0#8(&%(3$7"$(-3(,4-(-6"(8#,-3/"
§
○
L8#-"(^J(*3-6('84,3/"(#%7(8#,-3/" M"12"$&C"%-#8N
D&88(*"(56&-"
§
In(the(presence(of(glucose,(these(cells(do(not(produce(B-Gal(because(
they(have(glucose
§
B-Gal(gene(stays(silent
§
○
>
T=(-6"("%:9C"(&/("12$"//"7@(5&88(*"(*84"(3%(28#-">
`635/(-6"(235"$(3=(-6"(PA0#8(-338(#%7(>
Shows,the,effect,of,environmental,conditions,on,a,specific,gene>
4.(To(identify(the(required(genes(for(lactose(metabolism,(Monod(and(François(Jacob(
isolated(E.(coli(mutants(that(could(not(metabolize(lactose.
Genetic,screeningJ(#22$3#,6(-3('"%3C"(/-479(56"$"(934($#%73C89(*$"#G('"%"/(
#%7(833G(=3$(26"%3-92"(3=(&%-"$"/-
>
T/38#-&%'(C4-#%-/(5&-6($"/2",-(-3(#(2#$-&,48#$(-$#&-(&/(#(-53A/-"2(2$3,"//;
0"%"$#-"(#(8#$'"(%4C*"$(3=(&%7&.&74#8/(5&-6(C4-#-&3%/(#-($#%73C(
83,#-&3%/(&%(-6"&$('"%3C"/;
`-#$-(5&-6(C4-#'"%&:&%'(/-"2(
§
?$"#-&%'($#%73C(,6#%'"/(&%(-6"('"%3C"(3=(-6"/"(3$'#%&/C/(
§
V;
a/"(genetic,screening 3%(-6"(C4-#%-/(-3(=&%7(&%7&.&74#8/(5&-6(7"=",-/(&%(
-6"(2$3,"//(3$(2#-65#9(&%(S4"/-&3%;(T%(-6&/(#22$3#,6@(5"(5&88(4/"(replica,
plating.
!33G(#-(26"%3-92"(#%7(/""(&=(#%9(3=(-6"(C4-#%-/(6#."(#(26"%3-92"(
,3%/&/-"%-(5&-6(#$"#(3=(/-479
§
_;
>
b35(-3(C4-#'"%&:"J
BQ`
○
ac(8&'6-
○
[A$#9/(Y?#%(73(,6$3C3/3C#8(,6#%'"@(56&,6(#==",-/(#(83-;(0"%"$#889(%3-(
4/"7;
○
>
Transposable,elements/mobile,DNA,elementsJ(#(/"S4"%,"(3=(RFH(-6#-(6#/(
2#$-&,48#$(RFH(/"S4"%,"/(3%("&-6"$("%7(-6#-(#8835(&-(-3(*"(,4-(34-(3=(3%"(
83,#-&3%(&%(-6"('"%3C"(#%7(&%/"$-"7(&%(#%3-6"$($#%73C(28#,"(&%(-6"('"%3C"
?3487(*$"#G(-6"('"%"(&=(&%/"$-"7(&%(-6"(C&778"(3=(#('"%"
○
H(5#9(-3(73(/-"2(V(3=('"%"-&,(/,$""%&%'
○
>
<"28&,#(28#-&%'
a/&%'($"28&,#(28#-&%'(-3('$35(,"88/(4%7"$(#(=#.3$#*8"(,3%7&-&3%(3=('$35-6>
L4-(."8."-(*83,G(3%(-32(-3(2&,G(42(/3C"(,"88/(=$3C("#,6(,383%9>
a/"(-6"(*83,G(-3(28#,"(/3C"(,"88/(3%(#%3-6"$(28#-"(-6#-(,#%(6#."(#(7&=="$"%-(
,3C23%"%-
>
?329&%'(,"88/(3%(7&=="$"%-(28#-"/(3=(7&=="$"%-(,3C23%"%-/>
I6"($"28&,#( 28#-&%'(#22$3#,6(-3(&7"%-&=9(C4-#%-(,"88/
0$35(C4-#%-(*#,-"$(,383%&"/(3%(C#/-"$(28#-"/(,3%-#&%&%'(#(C"7&4C(5&-6(
'84,3/"
Q4-#%-/(/63487('$35(3%('84,3/"@(73%E-(%""7(#%9-6&%'(5&-6(PA0#8
○
H;
I$#%/="$(,"88/(=$3C("#,6(,383%9(-3(#(2&","(3=(/-"$&8&:"7(."8."-;
L&,G(42(,383%&"/(-3(C3."(-3(#%3-6"$(28#-"
○
P;
I$#%/="$(,"88/(-3(#(28#-"(5&-6(#(C"7&4C(,3%-#&%&%'(3%89(8#,-3/"(d-6&/(%"5(28#-"(
&/(,#88"7( #($"28&,#(28#-"
Q3/-(3=(-6"(-&C"@(5&88('$35(3%(8#,-3/"
○
D6"%(,$"#-&%'($#%73C(C4-#-&3%/@(4/4#889(73%E-(6&-(56#-(934(5#%-(-3(
/-479
○
?;
?3C2#$"(-6"(,383%&"/(3%(-6"(C#/-"$(28#-"(#%7($"28&,#(28#-"
e%35(56#-(,383%&"/(/63487('$35(3%("#,6(28#-"
○
T=(-6"$"(#$"(_f(,383%&"/(3%('84,3/"(#%7(Vg(3%(8#,-3/"@(934(,#%(=&%7(934$(
C4-#%-
○
R;
4;(L$"7&,-(56"-6"$(#(*#,-"$(,383%9(5&-6(#(C4-#-&3%(&%(#($"S4&$"7('"%"(=3$(8#,-3/"(
C"-#*38&/C(5&88('$35(3%J
H%(#'#$(28#-"(,3%-#&%&%'(3%89('84,3/";
YesA.
R3%E-(6#."(#%9-6&%'(-3(73(5&-6('84,3/"(C"-#*38&/C
○
F3P;
T;
H%(#'#$(28#-"(,3%-#&%&%'(3%89(8#,-3/";
h"/H;
NoB.
T=(934E."(7&/$42-"7(&-/(#*&8&-9(-3(4/"(8#,-3/"(#/(#%("%"$'9(/34$,"
○
TT;
I6"(-6$""(B;(,38&('"%"/(&%.38."7(&%(8#,-3/"(C"-#*38&/C(5"$"(%#C"7(8#,i@(8#,h@(#%7(8#,T
8#,iAC4-#%-/(8#,G(=4%,-&3%#8(B-gal>
8#,hAC4-#%-/(8#,G(-6"(C"C*$#%"(2$3-"&% galactoside,permease #%7(/3(,#%%3-(
-$#%/23$-(8#,-3/"(&%-3(-6"(,"88
I3('"-(697$326&8&,(/4*/-#%,"(#,$3//(28#/C#(C"C*$#%"@(%""7(-3(C#G"(&-(
2"$C"#*8"(-3(-6"(,#$*3697$#-"(
○
>
8#,TAC4-#%-/(#$"(,#88"7(constitutive,mutants *",#4/"(-6"9(2$374,"(XA
'#8#,-3/&7#/"(#%7('#8#,-3/&7"(2"$C"#/"("."%(56"%(8#,-3/"(&/(#*/"%-;
Constitutive,mutantsJ(-4$%('"%"/(3%
○
D&88("12$"//(&-($"'#$78"//(3=(/4'#$(2$"/"%-
○
>
I6"(A*9(-6"('"%"(C"#%/(%488(C4-#-&3%>
I6"(8#,i(#%7(8#,h('"%"/(,37"(=3$(2$3-"&%/(&%.38."7(&%(8#,-3/"(C"-#*38&/C@(56&8"(-6"(
8#,T('"%"(2$374,-(/"$."/(#($"'48#-3$9(=4%,-&3%;
D6"%(934(*$"#G(-6"($"2$"//3$(8#,T(-6"%(735%/-$"#C(2$3-"&%/(#$"(#85#9/(*"&%'(
8#7"(&%(-6"(,"88
>
T%(-6"(#*/"%,"(3=(8#,-3/"@(-6"(8#,T('"%"(2$374,-(/64-/(735%("12$"//&3%(3=(8#,i(
#%7(8#,h;(D6"%(8#,-3/"(&/(2$"/"%-@(635"."$@(-$#%/,$&2-&3%(3=(8#,i(#%7(8#,h(&/(
&%74,"7;
>
j4$-6"$(/-47&"/($"."#8"7(-6#-(-6"(8#,i@(8#,h@(#%7(8#,T('"%"/(#$"(83,#-"7(,83/"(
-3'"-6"$(3%(-6"(,&$,48#$(B;(,38&(,6$3C3/3C";(I6&/(/4''"/-"7(-6#-(8#,T(,3487(
,3%-$38(*3-6(8#,i(#%7(8#,h;
>
Prokaryotic*Gene*Regulation*I
D"7%"/7#9@( H2$&8(VV@(_fVk VVJ\k(HQ
!"#$%&%'()*+",-&."/
Explain(the(general(mechanisms(of(gene(regulation.(1.
Describe(the(role(of(lactose(in(the(induction(of(β-Galactosidase(in(E.(coli.(2.
Design(an(experiment(using(indicator(plates(coated(with(X-Gal(to(assay(β-
Galactosidase(activity.(
3.
Explain(how(replica(plating(was(used(in(a(genetic(screen(to(identify(the(lacZ,(
lacY,(and(lacI(genes.
4.
1.(A(cell(does(not(express(all(of(its(genes(all(of(the(time.(
0"%"("12$"//&3%(3,,4$/(56"%(#('"%"(2$374,-(&/(#,-&."89(*"&%'(/9%-6"/&:"7(#%7(
4/"7(&%(#(,"88;(<"'48#-&3%(3=('"%"("12$"//&3%(&/(,$&-&,#8(-3(-6"("==&,&"%-(4/"(3=(
$"/34$,"/(#%7(-64/(/4$.&.#8;(
>
?"88/(#$"(."$9(/"8",-&."(#*34-(-6"('"%"/(-6"9("12$"//@(635(/-$3%'89(-6"9(#$"(
"12$"//"7@(#%7(56"%(-6"9(#$"("12$"//"7;(
>
0"%"/(,#%(*"(4%7"$(-$#%/,$&2-&3%#8@(-$#%/8#-&3%#8@(3$(23/-A-$#%/8#-&3%#8(,3%-$38>
B12$"//&%'(-6"C(#88(-6"(-&C"(
D3487(*"("%"$'"-&,#889( 4%=#.3$#*8"
○
D3487%E-(6#."(/2",&=&,(,"88( -92"/
F""7(-3(C#G"(7&/-&%,-(-&//4"/(#%7(3$'#%/
§
○
>
Transcriptional,control 3,,4$/(56"%(-6"(,"88(73"/(%3-(2$374,"(C<FH;(
I6"(,"88( #.3&7/(-6"(2$374,-&3%(3=(-6"/"('"%"/(*9(4-&8&:&%'($"'48#-3$9(2$3-"&%/(
-6#-(2$"."%-(<FH(2389C"$#/"(=$3C(*&%7&%'(-3(#(2$3C3-"$
>
D6#-(934(%""7(-3(C#G"(#%(C<FH>
<"'48#-"(&=($"'48#-3$9(2$3-"&%/(#$"(#,-&."(3$("."%(C#7">
Translational,control #8835/(-6"(,"88( -3(2$"."%-(-6"(-$#%/8#-&3%(3=(#%(C<FH(C38",48"(
-6#-(6#/(#8$"#79(*""%(-$#%/,$&*"7;(
I6&/(,#%(3,,4$(-6$34'6(C#%9(C",6#%&/C/>
<"'48#-3$9(C38",48"/(,#%(/2""7(42(C<FH(7"'$#7#-&3%;>
I$#%/8#-&3%(&%&-&#-&3%(,#%(*"(#8-"$"7>
I$#%/8#-&3%(2$3-"&%/(,#%(*"(#==",-"7;>
miRNAJ(/63$-(%4,8"&,(#,&7(/-$"-,6"/(-6#-(#$"(,3C28"C"%-#$9(-3(-#$'"-(<FH/K(#,-(
-6$34'6(,3C28"C"%-#$9(*#/"(2#&$&%'(5&-6(-6"(C<FH(-3(7"'$#7"(C<FH
F#-4$#8(2$3,"//(3=($"'48#-&%'(C<FH(8&="/2#%
○
?#%(&%+",-(#$-&=&,( C&<FH(&%(-6"(8#*(-3(,#4/"(RNA,silencingJ(#77(#$-&=&,(
<FH(-3(735%$"'48#-"(#('"%"
○
>
Post-translational ,3%-$38(3,,4$/(56"%(-6"(,"88(=#&8/(-3(#,-&.#-"(#(C#%4=#,-4$"7(
2$3-"&%(*9(,6"C&,#8(C37&=&,#-&3%
0$""%(/6#2"J(2$3-"&%(5&-6(-"$-&#$9(/6#2"
>
LJ(263/26#-"('$342(%"'#-&."89(,6#$'"7
H77&%'(&-(,6#%'"/(2$3-"&%/(/6#2"(#%7(-6"$"=3$"(=4%,-&3%
○
Phosphorylate 2$3-"&%(-3J
Activate 2$3-"&%(*9($"."#8&%'(#%(#,-&."(/&-"
§
Inhibit 2$3-"&%(*9(6&7&%'(#,-&."(/&-"
§
○
>
1. D6&,6(3=(-6"(=38835&%'(8"."8/(3=('"%"("12$"//&3%($"'48#-&3%(#8835/(-6"(C3/-(
"==&,&"%-(M&;";AAC3/-("%"$'"-&,#889(=#.3$#*8"N($"/23%/"(-3("%.&$3%C"%-#8(,6#%'"O(
transcriptional,control,
A.
-$#%/8#-&3%#8(,3%-$38(
P;
23/-A-$#%/8#-&3%#8(,3%-$38(
?;
2. D6&,6(3=(-6"(=38835&%'(8"."8/(3=('"%"("12$"//&3%($"'48#-&3%(#8835/(-6"(C3/-($#2&7(
$"/23%/"(-3("%.&$3%C"%-#8(,6#%'"O(
-$#%/,$&2-&3%#8(,3%-$38(
H;
-$#%/8#-&3%#8(,3%-$38(
P;
post-translational,control
C.
H88(-6$""(=3$C/(3=('"%"("12$"//&3%(,3%-$38(3,,4$(&%(*#,-"$&#
I$#%/,$&2-&3%#8(,3%-$38(&/(/835(*4-("==&,&"%-
Q3/-("%"$'"-&,#889(=#.3$#*8"
○
R3%E-(C#G"(C<FH
○
>
I$#%/8#-&3%#8(,3%-$38(#8835/(#(,"88(-3(S4&,G89(,6#%'"(56&,6(2$3-"&%/(#$"(
2$374,"7
Q#G&%'(C&<FH/(-3(/&8"%-(C<FH/(&/(%3-(-6"(C3/-("%"$'"-&,#889(=#.3$#*8"(3$(
"==&,&"%-(C"-637(-3(/64-(735%(#('"%"(M4/"(-$#%/,$&2-&3%#8N
○
>
L3/-A-$#%/8#-&3%#8(,3%-$38(2$3.&7"/(-6"(C3/-($#2&7($"/23%/"(*4-(&/("%"$'"-&,#889(
"12"%/&."
P"/-(=3$("%.&$3%C"%-#8(,6#%'"
○
T=(934(+4/-(/-32(-$#%/,$&2-&3%@(934(#8$"#79(6#."(=4%,-&3%#8(2$3-"&%(&%(-6"(
,"88( -6#-(5&88(G""2(53$G&%'("."%(934(&=(934(73%E-(C#G"(#%9(C3$"(C<FH/(
M569(-6"9(73%E-(4/"(-$#%/,$&2-&3%#8N
L$3-"&%(53487(*"(7"'$#7"7@(*4-(%3-(#/(S4&,G89(#/(&=(934(-4$%"7(3==(
-6"(2$3-"&%/
§
○
>
2.(Lactose(induces(β-Galactosidase(expression(in(E.(coli.
!#,-3/"(U(V('84,3/"(W(V('#8#,-3/">
B;(,38&(%""7/(#%("%:9C"(-3(*$"#G(42(-6"(*3%7(3=('84,3/"(#%7('#8#,-3/">
B;(,38&(2$374,"/(6&'6(8"."8/(3= β-galactosidase MXA'#8N(3%89(56"%(8#,-3/"(&/(
2$"/"%-(&%(-6"("%.&$3%C"%-
>
I64/@(8#,-3/"(#,-/(#/(#%(inducerJ(#(C38",48"(-6#-(/-&C48#-"/(-6"("12$"//&3%(3=(#(
/2",&=&,('"%"
>
I6"(8"."8( 3=("12$"//&3%(3=(7&=="$"%-('"%"/(,#%(*"(6&'689(.#$&#*8"Y-6&/(#8835/(,"88/(-3(
$"/23%7(-3("%.&$3%C"%-#8(,6#%'"/
B;(,38&Z/(2$"="$$"7(,#$*3%(/34$,"(&/('84,3/"(=3$('89,389/&/>
P"=3$"(&-(,#%(4-&8&:"(8#,-3/"@(B;(,38&(C4/-(-$#%/23$-(&-(&%-3(-6"(,"88@(56"$"(-6"(
"%:9C"(XA'#8#,-3/&7#/"(,#%(,8"#."(&-(-3(2$374,"('84,3/"(#%7('#8#,-3/"
>
3.(X-Gal(is(a(dye(used(to(detect(β-Galactosidase(activity
I3(G%35(56&,6(,"88/(#$"(,$"#-&%'(-6"("%:9C"
H//"//(56"-6"$(-6"(/2",&=&,("%:9C"(&/(3$(&/%E-("12$"//"7(*([A0#8(-338
○
>
[A'#8(833G/(G&%7(3=(8&G"(8#,-3/"
D6"%(934(,4-(-6"('89,3/&7&,(8&%G#'"@(934(=$""(42(-6"([(C38",48"/(-6#-(#$"(
,383$8"//
○
T%(-6"(,4-(=3$C@(-6"9(2$",&2&-#-"(#%7(*",3C"(*84"
○
>
I6"(,383$8"//(79"([A0#8(&/(#(7&C"$(,3C23/"7(3=(#([(M\A*$3C3A ]A,683$3A^A&%73898(
C3%3C"$N(#%7(0#8#,-3/";(
[(&/(,383$8"//
○
>
XA0#8#,-3/&7#/"(,8"#."/(-6"(8&%G#'"(*"-5""%(-6"(\A*$3C3A]A ,683$3A^A&%73898(
C3%3C"$(#%7(0#8#,-3/";(
?4-(7&C"$(&%-3('84,3/"(#%7('#8#,-3/"(-3(#8835(-6"(C38",48"/(-3(7&C"$A&:"
○
>
I6"(7&C"$&:#-&3%(3=(\A*$3C3A]A ,683$3A^A&%73898(C3%3C"$/($"/48-/(&%(-6"(
=3$C#-&3%(3=(#(*84"(2$",&2&-#-";
L$",&2&-#-"(&/([[
○
>
T%7&,#-3$(28#-"/(,3#-"7(5&-6([A0#8(,#%(*"(4/"7(-3(7"-",-(XA0#8#,-3/&7#/"(#,-&.&-9
?"88/("12$"//&%'("%:9C"(#$"(*84">
3. T%(!"#$%&%'?#-#89-&,/@(7"/&'%(#%("12"$&C"%-(4/&%'(&%7&,#-3$(28#-"/(-3(-"/-(&=(B;(,38&(
2$374,"(XA0#8#,-3/&7#/"(56"%(*3-6('84,3/"(#%7(8#,-3/"(#$"(2$"/"%-;
L8#-"/J
L8#-"(VJ('84,3/"(3%89 M,3%-$38N
D&88(*"(56&-"(,383%&"/
§
D&88(%3-(*"(#*8"(-3(,4-([A'#8(79"(-3(C#G"(2$",&2&-#-"
§
○
L8#-"(_J(8#,-3/"(3%89 M,3%-$38N
D&88(*"(*84"
§
F""7(-3(C#G"(PA0#8(&%(3$7"$(-3(,4-(-6"(8#,-3/"
§
○
L8#-"(^J(*3-6('84,3/"(#%7(8#,-3/" M"12"$&C"%-#8N
D&88(*"(56&-"
§
In(the(presence(of(glucose,(these(cells(do(not(produce(B-Gal(because(
they(have(glucose
§
B-Gal(gene(stays(silent
§
○
>
T=(-6"("%:9C"(&/("12$"//"7@(5&88(*"(*84"(3%(28#-">
`635/(-6"(235"$(3=(-6"(PA0#8(-338(#%7(>
Shows,the,effect,of,environmental,conditions,on,a,specific,gene>
4.(To(identify(the(required(genes(for(lactose(metabolism,(Monod(and(François(Jacob(
isolated(E.(coli(mutants(that(could(not(metabolize(lactose.
Genetic,screeningJ(#22$3#,6(-3('"%3C"(/-479(56"$"(934($#%73C89(*$"#G('"%"/(
#%7(833G(=3$(26"%3-92"(3=(&%-"$"/-
>
T/38#-&%'(C4-#%-/(5&-6($"/2",-(-3(#(2#$-&,48#$(-$#&-(&/(#(-53A/-"2(2$3,"//;
0"%"$#-"(#(8#$'"(%4C*"$(3=(&%7&.&74#8/(5&-6(C4-#-&3%/(#-($#%73C(
83,#-&3%/(&%(-6"&$('"%3C"/;
`-#$-(5&-6(C4-#'"%&:&%'(/-"2(
§
?$"#-&%'($#%73C(,6#%'"/(&%(-6"('"%3C"(3=(-6"/"(3$'#%&/C/(
§
V;
a/"(genetic,screening 3%(-6"(C4-#%-/(-3(=&%7(&%7&.&74#8/(5&-6(7"=",-/(&%(
-6"(2$3,"//(3$(2#-65#9(&%(S4"/-&3%;(T%(-6&/(#22$3#,6@(5"(5&88(4/"(replica,
plating.
!33G(#-(26"%3-92"(#%7(/""(&=(#%9(3=(-6"(C4-#%-/(6#."(#(26"%3-92"(
,3%/&/-"%-(5&-6(#$"#(3=(/-479
§
_;
>
b35(-3(C4-#'"%&:"J
BQ`
○
ac(8&'6-
○
[A$#9/(Y?#%(73(,6$3C3/3C#8(,6#%'"@(56&,6(#==",-/(#(83-;(0"%"$#889(%3-(
4/"7;
○
>
Transposable,elements/mobile,DNA,elementsJ(#(/"S4"%,"(3=(RFH(-6#-(6#/(
2#$-&,48#$(RFH(/"S4"%,"/(3%("&-6"$("%7(-6#-(#8835(&-(-3(*"(,4-(34-(3=(3%"(
83,#-&3%(&%(-6"('"%3C"(#%7(&%/"$-"7(&%(#%3-6"$($#%73C(28#,"(&%(-6"('"%3C"
?3487(*$"#G(-6"('"%"(&=(&%/"$-"7(&%(-6"(C&778"(3=(#('"%"
○
H(5#9(-3(73(/-"2(V(3=('"%"-&,(/,$""%&%'
○
>
<"28&,#(28#-&%'
a/&%'($"28&,#(28#-&%'(-3('$35(,"88/(4%7"$(#(=#.3$#*8"(,3%7&-&3%(3=('$35-6>
L4-(."8."-(*83,G(3%(-32(-3(2&,G(42(/3C"(,"88/(=$3C("#,6(,383%9>
a/"(-6"(*83,G(-3(28#,"(/3C"(,"88/(3%(#%3-6"$(28#-"(-6#-(,#%(6#."(#(7&=="$"%-(
,3C23%"%-
>
?329&%'(,"88/(3%(7&=="$"%-(28#-"/(3=(7&=="$"%-(,3C23%"%-/>
I6"($"28&,#( 28#-&%'(#22$3#,6(-3(&7"%-&=9(C4-#%-(,"88/
0$35(C4-#%-(*#,-"$(,383%&"/(3%(C#/-"$(28#-"/(,3%-#&%&%'(#(C"7&4C(5&-6(
'84,3/"
Q4-#%-/(/63487('$35(3%('84,3/"@(73%E-(%""7(#%9-6&%'(5&-6(PA0#8
○
H;
I$#%/="$(,"88/(=$3C("#,6(,383%9(-3(#(2&","(3=(/-"$&8&:"7(."8."-;
L&,G(42(,383%&"/(-3(C3."(-3(#%3-6"$(28#-"
○
P;
I$#%/="$(,"88/(-3(#(28#-"(5&-6(#(C"7&4C(,3%-#&%&%'(3%89(8#,-3/"(d-6&/(%"5(28#-"(
&/(,#88"7( #($"28&,#(28#-"
Q3/-(3=(-6"(-&C"@(5&88('$35(3%(8#,-3/"
○
D6"%(,$"#-&%'($#%73C(C4-#-&3%/@(4/4#889(73%E-(6&-(56#-(934(5#%-(-3(
/-479
○
?;
?3C2#$"(-6"(,383%&"/(3%(-6"(C#/-"$(28#-"(#%7($"28&,#(28#-"
e%35(56#-(,383%&"/(/63487('$35(3%("#,6(28#-"
○
T=(-6"$"(#$"(_f(,383%&"/(3%('84,3/"(#%7(Vg(3%(8#,-3/"@(934(,#%(=&%7(934$(
C4-#%-
○
R;
4;(L$"7&,-(56"-6"$(#(*#,-"$(,383%9(5&-6(#(C4-#-&3%(&%(#($"S4&$"7('"%"(=3$(8#,-3/"(
C"-#*38&/C(5&88('$35(3%J
H%(#'#$(28#-"(,3%-#&%&%'(3%89('84,3/";
YesA.
R3%E-(6#."(#%9-6&%'(-3(73(5&-6('84,3/"(C"-#*38&/C
○
F3P;
T;
H%(#'#$(28#-"(,3%-#&%&%'(3%89(8#,-3/";
h"/H;
NoB.
T=(934E."(7&/$42-"7(&-/(#*&8&-9(-3(4/"(8#,-3/"(#/(#%("%"$'9(/34$,"
○
TT;
I6"(-6$""(B;(,38&('"%"/(&%.38."7(&%(8#,-3/"(C"-#*38&/C(5"$"(%#C"7(8#,i@(8#,h@(#%7(8#,T
8#,iAC4-#%-/(8#,G(=4%,-&3%#8(B-gal>
8#,hAC4-#%-/(8#,G(-6"(C"C*$#%"(2$3-"&% galactoside,permease #%7(/3(,#%%3-(
-$#%/23$-(8#,-3/"(&%-3(-6"(,"88
I3('"-(697$326&8&,(/4*/-#%,"(#,$3//(28#/C#(C"C*$#%"@(%""7(-3(C#G"(&-(
2"$C"#*8"(-3(-6"(,#$*3697$#-"(
○
>
8#,TAC4-#%-/(#$"(,#88"7(constitutive,mutants *",#4/"(-6"9(2$374,"(XA
'#8#,-3/&7#/"(#%7('#8#,-3/&7"(2"$C"#/"("."%(56"%(8#,-3/"(&/(#*/"%-;
Constitutive,mutantsJ(-4$%('"%"/(3%
○
D&88("12$"//(&-($"'#$78"//(3=(/4'#$(2$"/"%-
○
>
I6"(A*9(-6"('"%"(C"#%/(%488(C4-#-&3%>
I6"(8#,i(#%7(8#,h('"%"/(,37"(=3$(2$3-"&%/(&%.38."7(&%(8#,-3/"(C"-#*38&/C@(56&8"(-6"(
8#,T('"%"(2$374,-(/"$."/(#($"'48#-3$9(=4%,-&3%;
D6"%(934(*$"#G(-6"($"2$"//3$(8#,T(-6"%(735%/-$"#C(2$3-"&%/(#$"(#85#9/(*"&%'(
8#7"(&%(-6"(,"88
>
T%(-6"(#*/"%,"(3=(8#,-3/"@(-6"(8#,T('"%"(2$374,-(/64-/(735%("12$"//&3%(3=(8#,i(
#%7(8#,h;(D6"%(8#,-3/"(&/(2$"/"%-@(635"."$@(-$#%/,$&2-&3%(3=(8#,i(#%7(8#,h(&/(
&%74,"7;
>
j4$-6"$(/-47&"/($"."#8"7(-6#-(-6"(8#,i@(8#,h@(#%7(8#,T('"%"/(#$"(83,#-"7(,83/"(
-3'"-6"$(3%(-6"(,&$,48#$(B;(,38&(,6$3C3/3C";(I6&/(/4''"/-"7(-6#-(8#,T(,3487(
,3%-$38(*3-6(8#,i(#%7(8#,h;
>
Prokaryotic*Gene*Regulation*I
D"7%"/7#9@( H2$&8(VV@(_fVk VVJ\k(HQ
Document Summary
Describe the role of lactose in the induction of - galactosidase in e. coli. Design an experiment using indicator plates coated with x-gal to assay - Explain how replica plating was used in a genetic screen to identify the lacz, lacy, and laci genes: a cell does not express all of its genes all of the time. Gene expression occurs when a gene product is actively being synthesized and used in a cell. Regulation of gene expression is critical to the efficient use of resources and thus survival. Cells are very selective about the genes they express, how strongly they are expressed, and when they are expressed. Genes can be under transcriptional, translational, or post-translational control. Transcriptional control occurs when the cell does not produce mrna. The cell avoids the production of these genes by utilizing regulatory proteins that prevent rna polymerase from binding to a promoter. Regulate if regulatory proteins are active or even made.
