306:, among others, have been seen to regulate the activity of activators. Depending on the chemical group being added, as well as the nature of the activator itself, post-translational modifications can either increase or decrease the activity of an activator. For example, acetylation has been seen to increase the activity of some activators through mechanisms such as increasing DNA-binding affinity. On the other hand, ubiquitination decreases the activity of activators, as ubiquitin marks proteins for degradation after they have performed their respective functions.
157:. Activators also have unique sequences of amino acids with side chains that are able to interact with the functional groups in DNA. Thus, the pattern of amino acid side chains making up an activator protein will be complementary to the surface features of the specific DNA regulatory sequence it was designed to bind to. The complementary interactions between the amino acids of the activator protein and the functional groups of the DNA create an "exact-fit" specificity between the activator and its regulatory DNA sequence.
252:
polymerase from this “stalled” state. Multiple mechanisms exist for releasing these "stalled" RNA polymerases. Activators may act simply as a signal to trigger the continued movement of the RNA polymerase. If the DNA is too condensed to allow RNA polymerase to continue transcription, activators may recruit proteins that can restructure the DNA so any blocks are removed. Activators may also promote the recruitment of elongation factors, which are necessary for the RNA polymerase to continue transcription.
391:
73:), thereby facilitating the binding of the general transcription machinery to the promoter. Other activators help promote gene transcription by triggering RNA polymerase to release from the promoter and proceed along the DNA. At times, RNA polymerase can pause shortly after leaving the promoter; activators also function to allow these "stalled" RNA polymerases to continue transcription.
387:(cAMP) is produced during glucose starvation; this molecule acts as an allosteric effector that binds to CAP and causes a conformational change that allows CAP to bind to a DNA site located adjacent to the lac promoter. CAP then makes a direct protein–protein interaction with RNA polymerase that recruits RNA polymerase to the lac promoter.
171:), and are thus controlled under the same regulatory sequence. In eukaryotes, genes tend to be transcribed individually, and each gene is controlled by its own regulatory sequences. Regulatory sequences where activators bind are commonly found upstream from the promoter, but they can also be found downstream or even within
351:
When maltose is present in the cell, it binds to the allosteric site of the activator protein, causing a conformational change in the DNA-binding domain of the activator. This conformational change "turns on" the activator by allowing it to bind to its specific regulatory DNA sequence. Binding of the
269:
Activators often must be "turned on" before they can promote gene transcription. The activity of activators is controlled by the ability of the activator to bind to its regulatory site along the DNA. The DNA-binding domain of the activator has an active form and an inactive form, which are controlled
347:
is controlled by gene activation. The genes that code for the enzymes responsible for maltose catabolism can only be transcribed in the presence of an activator.The activator that controls transcription of the maltose enzymes is "off" in the absence of maltose. In its inactive form, the activator is
204:
In prokaryotes, genes controlled by activators have promoters that are unable to strongly bind to RNA polymerase by themselves. Thus, activator proteins help to promote the binding of the RNA polymerase to the promoter. This is done through various mechanisms. Activators may bend the DNA in order to
319:
at the binding-site, meaning that the binding of one activator increases the affinity of the site to bind another activator (or in some cases another transcriptional regulator) thus making it easier for multiple activators to bind at the site. In these cases, the activators interact with each other
195:
Activator interactions with RNA polymerase are mostly direct in prokaryotes and indirect in eukaryotes. In prokaryotes, activators tend to make contact with the RNA polymerase directly in order to help bind it to the promoter. In eukaryotes, activators mostly interact with other proteins, and these
76:
The activity of activators can be regulated. Some activators have an allosteric site and can only function when a certain molecule binds to this site, essentially turning the activator on. Post-translational modifications to activators can also regulate activity, increasing or decreasing activity
260:
There are different ways in which the activity of activators themselves can be regulated, in order to ensure that activators are stimulating gene transcription at appropriate times and levels. Activator activity can increase or decrease in response to environmental stimuli or other intracellular
251:
Activators can promote gene transcription by signaling the RNA polymerase to move beyond the promoter and proceed along the DNA, initiating the beginning of transcription. The RNA polymerase can sometimes pause shortly after beginning transcription, and activators are required to release RNA
163:
Activator-binding sites may be located very close to the promoter or numerous base pairs away. If the regulatory sequence is located far away, the DNA will loop over itself (DNA looping) in order for the bound activator to interact with the transcription machinery at the promoter site.
183:
Binding of the activator to its regulatory sequence promotes gene transcription by enabling RNA polymerase activity. This is done through various mechanisms, such as recruiting transcription machinery to the promoter and triggering RNA polymerase to continue into elongation.
58:. The DNA site bound by the activator is referred to as an "activator-binding site". The part of the activator that makes protein–protein interactions with the general transcription machinery is referred to as an "activating region" or "activation domain".
112:
among others. These DNA-binding domains are specific to a certain DNA sequence, allowing activators to turn on only certain genes. Activation domains also come in a variety of types that are categorized based on the domain's amino acid sequence, including
227:
DNA is much more condensed in eukaryotes; thus, activators tend to recruit proteins that are able to restructure the chromatin so the promoter is more easily accessible by the transcription machinery. Some proteins will rearrange the layout of
277:
Activators in their inactive form are not bound to any allosteric effectors. When inactive, the activator is unable to bind to its specific regulatory sequence in the DNA, and thus has no regulatory effect on the transcription of genes.
314:
In prokaryotes, a lone activator protein is able to promote transcription. In eukaryotes, usually more than one activator assembles at the binding-site, forming a complex that acts to promote transcription. These activators bind
281:
When an allosteric effector binds to the allosteric site of an activator, a conformational change in the DNA-binding domain occurs, which allows the protein to bind to the DNA and increase gene transcription.
352:
activator to its regulatory site promotes RNA polymerase binding to the promoter and thus transcription, producing the enzymes that are needed to break down the maltose that has entered the cell.
324:, meaning that the rate of transcription that is achieved from multiple activators working together is much higher than the additive effects of the activators if they were working individually.
213:
In eukaryotes, activators have a variety of different target molecules that they can recruit in order to promote gene transcription. They can recruit other transcription factors and
46:
control over gene expression, as they function to promote gene transcription and, in some cases, are required for the transcription of genes to occur. Most activators are
224:. These coactivator molecules can then perform functions necessary for beginning transcription in place of the activators themselves, such as chromatin modifications.
205:
better expose the promoter so the RNA polymerase can bind more effectively. Activators may make direct contact with the RNA polymerase and secure it to the promoter.
192:
Activator-controlled genes require the binding of activators to regulatory sites in order to recruit the necessary transcription machinery to the promoter region.
100:
that functions to increase gene transcription by interacting with other molecules. Activator DNA-binding domains come in a variety of conformations, including the
80:
In some cells, usually eukaryotes, multiple activators can bind to the binding-site; these activators tend to bind cooperatively and interact synergistically.
160:
Most activators bind to the major grooves of the double helix, as these areas tend to be wider, but there are some that will bind to the minor grooves.
951:
1097:
807:
717:
145:
of the base pairs are exposed. The sequence of the DNA thus creates a unique pattern of surface features, including areas of possible
427:
1301:
291:
237:
1394:
384:
442:
365:
70:
243:
All of these recruited molecules work together in order to ultimately recruit the RNA polymerase to the promoter site.
121:-rich, and acidic domains. These domains are not as specific, and tend to interact with a variety of target molecules.
944:
706:
Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Morgan, David; Raff, Martin; Roberts, Keith; Walter, Peter (2015).
977:
1174:
1110:
1080:
1058:
1354:
1329:
1296:
968:
960:
422:
39:
1349:
1317:
1291:
1275:
964:
412:
214:
1184:
937:
417:
221:
97:
1368:
1363:
1231:
1133:
369:
1265:
1145:
1039:
887:
457:
233:
35:
1248:
1216:
1102:
1076:
796:
Madigan, Michael T; Bender, Kelly S; Buckley, Daniel H; Sattley, Matthew W; Stahl, David A (2018).
316:
271:
62:
55:
51:
47:
61:
Most activators function by binding sequence-specifically to a regulatory DNA site located near a
1017:
437:
154:
93:
862:
Griffiths, Anthony J.F.; Gelbart, William M.; Miller, Jeffrey H.; Lewontin, Richard C. (1999).
1336:
915:
907:
813:
803:
723:
713:
595:
577:
407:
1258:
1241:
899:
585:
569:
343:
142:
101:
1122:
295:
125:
17:
929:
1332:
1320:
1270:
590:
557:
109:
89:
66:
390:
1388:
1034:
150:
146:
65:
and making protein–protein interactions with the general transcription machinery (
1221:
1189:
1092:
299:
105:
863:
1373:
1067:
1022:
1012:
1007:
1002:
997:
573:
452:
373:
229:
911:
817:
727:
581:
1029:
447:
303:
118:
919:
903:
599:
797:
707:
1236:
1226:
1196:
1063:
338:
321:
294:
that have an effect on their activity within a cell. Processes such as
128:
that are responsible for turning the activators themselves on and off.
114:
348:
unable to bind to DNA and promote transcription of the maltose genes.
992:
432:
172:
168:
196:
proteins will then be the ones to interact with the RNA polymerase.
77:
depending on the type of modification and activator being modified.
712:(Sixth ed.). New York, NY: Garland Science. pp. 373–392.
1253:
1105:
389:
236:). Other proteins affect the binding between histones and DNA via
1324:
1154:
1085:
888:"Transcription activation by catabolite activator protein (CAP)"
933:
240:, allowing the DNA tightly wrapped into nucleosomes to loosen.
96:
that binds to a DNA sequence specific to the activator, and an
27:
Protein that increases transcription of a gene or set of genes
42:
of a gene or set of genes. Activators are considered to have
167:
In prokaryotes, multiple genes can be transcribed together (
802:(Fifteenth ed.). NY, NY: Pearson. pp. 174–179.
864:"The Basics of Prokaryotic Transcriptional Regulation"
558:"Transcriptional activators and activation mechanisms"
232:
along the DNA in order to expose the promoter site (
1345:
1310:
1284:
1209:
1167:
1144:
1121:
1057:
1050:
985:
976:
886:Busby, Steve; Ebright, Richard H (1999-10-22).
945:
217:that are needed in transcription initiation.
8:
234:ATP-dependent chromatin remodeling complexes
141:Within the grooves of the DNA double helix,
1054:
982:
952:
938:
930:
220:Activators can recruit molecules known as
589:
274:to the allosteric site of the activator.
137:Activator binding to regulatory sequences
238:post-translational histone modifications
179:Functions to increase gene transcription
469:
88:Activator proteins consist of two main
372:(CRP), activates transcription at the
1098:Histone acetylation and deacetylation
857:
855:
853:
851:
849:
847:
791:
789:
787:
785:
783:
781:
779:
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771:
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757:
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651:
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647:
645:
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641:
639:
637:
635:
633:
631:
629:
551:
549:
547:
545:
543:
541:
539:
537:
535:
533:
531:
529:
527:
525:
523:
521:
519:
517:
515:
513:
511:
509:
507:
505:
503:
501:
499:
497:
495:
493:
270:by the binding of molecules known as
7:
881:
879:
877:
845:
843:
841:
839:
837:
835:
833:
831:
829:
827:
755:
753:
751:
749:
747:
745:
743:
741:
739:
737:
627:
625:
623:
621:
619:
617:
615:
613:
611:
609:
491:
489:
487:
485:
483:
481:
479:
477:
475:
473:
290:Some activators are able to undergo
25:
428:Glossary of gene expression terms
333:Regulation of maltose catabolism
292:post-translational modifications
286:Post-translational modifications
265:Activation of activator proteins
1302:Archaeal transcription factor B
799:Brock Biology of Microorganisms
385:Cyclic adenosine monophosphate
1:
709:Molecular Biology of the Cell
443:Regulation of gene expression
71:general transcription factors
892:Journal of Molecular Biology
366:catabolite activator protein
1411:
978:Transcriptional regulation
368:(CAP), otherwise known as
56:promoter-proximal elements
1175:Transcription coregulator
1111:Histone acetyltransferase
1081:Histone methyltransferase
1059:Histone-modifying enzymes
574:10.1007/s13238-011-1101-7
247:Release of RNA polymerase
124:Activators can also have
18:Transcriptional activator
423:Eukaryotic transcription
256:Regulation of activators
155:hydrophobic interactions
1276:Internal control region
868:Modern Genetic Analysis
413:Bacterial transcription
904:10.1006/jmbi.1999.3161
418:Coactivator (genetics)
398:
1395:Transcription factors
1369:Intrinsic termination
1134:DNA methyltransferase
393:
370:cAMP receptor protein
1146:Chromatin remodeling
458:Transcription factor
272:allosteric effectors
48:DNA-binding proteins
36:transcription factor
1103:Histone deacetylase
1093:Histone demethylase
1077:Histone methylation
132:Mechanism of action
562:Protein & Cell
438:Promoter (biology)
399:
356:Regulation of the
94:DNA-binding domain
30:A transcriptional
1382:
1381:
1337:RNA polymerase II
1205:
1204:
1163:
1162:
870:– via NCBI.
809:978-0-13-426192-8
719:978-0-8153-4432-2
408:CRISPR activation
379:of the bacterium
337:The breakdown of
143:functional groups
98:activation domain
38:) that increases
16:(Redirected from
1402:
1259:Response element
1242:Response element
1055:
983:
954:
947:
940:
931:
924:
923:
883:
872:
871:
859:
822:
821:
793:
732:
731:
703:
604:
603:
593:
556:Ma, Jun (2011).
553:
397:operon in detail
381:Escherichia coli
344:Escherichia coli
147:hydrogen bonding
126:allosteric sites
102:helix-turn-helix
21:
1410:
1409:
1405:
1404:
1403:
1401:
1400:
1399:
1385:
1384:
1383:
1378:
1353:
1347:
1341:
1306:
1280:
1201:
1159:
1140:
1123:DNA methylation
1117:
1061:
1046:
972:
958:
928:
927:
885:
884:
875:
861:
860:
825:
810:
795:
794:
735:
720:
705:
704:
607:
568:(11): 879–888.
555:
554:
471:
466:
404:
362:
335:
330:
322:synergistically
312:
296:phosphorylation
288:
267:
258:
249:
211:
202:
190:
181:
175:in eukaryotes.
139:
134:
86:
28:
23:
22:
15:
12:
11:
5:
1408:
1406:
1398:
1397:
1387:
1386:
1380:
1379:
1377:
1376:
1371:
1366:
1360:
1358:
1343:
1342:
1340:
1339:
1333:RNA polymerase
1327:
1321:RNA polymerase
1314:
1312:
1308:
1307:
1305:
1304:
1299:
1294:
1288:
1286:
1282:
1281:
1279:
1278:
1273:
1268:
1263:
1262:
1261:
1256:
1246:
1245:
1244:
1239:
1234:
1229:
1224:
1213:
1211:
1207:
1206:
1203:
1202:
1200:
1199:
1194:
1193:
1192:
1187:
1182:
1171:
1169:
1165:
1164:
1161:
1160:
1158:
1157:
1151:
1149:
1142:
1141:
1139:
1138:
1137:
1136:
1128:
1126:
1119:
1118:
1116:
1115:
1114:
1113:
1108:
1095:
1090:
1089:
1088:
1073:
1071:
1052:
1048:
1047:
1045:
1044:
1043:
1042:
1037:
1027:
1026:
1025:
1020:
1015:
1010:
1005:
1000:
989:
987:
980:
974:
973:
959:
957:
956:
949:
942:
934:
926:
925:
898:(2): 199–213.
873:
823:
808:
733:
718:
605:
468:
467:
465:
462:
461:
460:
455:
450:
445:
440:
435:
430:
425:
420:
415:
410:
403:
400:
361:
354:
334:
331:
329:
326:
311:
308:
304:ubiquitination
287:
284:
266:
263:
257:
254:
248:
245:
210:
207:
201:
198:
189:
186:
180:
177:
138:
135:
133:
130:
110:leucine zipper
85:
82:
67:RNA polymerase
34:is a protein (
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
1407:
1396:
1393:
1392:
1390:
1375:
1372:
1370:
1367:
1365:
1362:
1361:
1359:
1356:
1351:
1344:
1338:
1334:
1331:
1328:
1326:
1322:
1319:
1316:
1315:
1313:
1309:
1303:
1300:
1298:
1295:
1293:
1290:
1289:
1287:
1283:
1277:
1274:
1272:
1269:
1267:
1264:
1260:
1257:
1255:
1252:
1251:
1250:
1247:
1243:
1240:
1238:
1235:
1233:
1230:
1228:
1225:
1223:
1220:
1219:
1218:
1215:
1214:
1212:
1208:
1198:
1195:
1191:
1188:
1186:
1183:
1181:
1178:
1177:
1176:
1173:
1172:
1170:
1166:
1156:
1153:
1152:
1150:
1147:
1143:
1135:
1132:
1131:
1130:
1129:
1127:
1124:
1120:
1112:
1109:
1107:
1104:
1101:
1100:
1099:
1096:
1094:
1091:
1087:
1084:
1083:
1082:
1078:
1075:
1074:
1072:
1069:
1065:
1060:
1056:
1053:
1049:
1041:
1040:trp repressor
1038:
1036:
1035:lac repressor
1033:
1032:
1031:
1028:
1024:
1021:
1019:
1016:
1014:
1011:
1009:
1006:
1004:
1001:
999:
996:
995:
994:
991:
990:
988:
984:
981:
979:
975:
970:
966:
962:
961:Transcription
955:
950:
948:
943:
941:
936:
935:
932:
921:
917:
913:
909:
905:
901:
897:
893:
889:
882:
880:
878:
874:
869:
865:
858:
856:
854:
852:
850:
848:
846:
844:
842:
840:
838:
836:
834:
832:
830:
828:
824:
819:
815:
811:
805:
801:
800:
792:
790:
788:
786:
784:
782:
780:
778:
776:
774:
772:
770:
768:
766:
764:
762:
760:
758:
756:
754:
752:
750:
748:
746:
744:
742:
740:
738:
734:
729:
725:
721:
715:
711:
710:
702:
700:
698:
696:
694:
692:
690:
688:
686:
684:
682:
680:
678:
676:
674:
672:
670:
668:
666:
664:
662:
660:
658:
656:
654:
652:
650:
648:
646:
644:
642:
640:
638:
636:
634:
632:
630:
628:
626:
624:
622:
620:
618:
616:
614:
612:
610:
606:
601:
597:
592:
587:
583:
579:
575:
571:
567:
563:
559:
552:
550:
548:
546:
544:
542:
540:
538:
536:
534:
532:
530:
528:
526:
524:
522:
520:
518:
516:
514:
512:
510:
508:
506:
504:
502:
500:
498:
496:
494:
492:
490:
488:
486:
484:
482:
480:
478:
476:
474:
470:
463:
459:
456:
454:
451:
449:
446:
444:
441:
439:
436:
434:
431:
429:
426:
424:
421:
419:
416:
414:
411:
409:
406:
405:
401:
396:
392:
388:
386:
382:
378:
376:
371:
367:
359:
355:
353:
349:
346:
345:
340:
332:
327:
325:
323:
318:
317:cooperatively
309:
307:
305:
301:
297:
293:
285:
283:
279:
275:
273:
264:
262:
255:
253:
246:
244:
241:
239:
235:
231:
225:
223:
218:
216:
208:
206:
199:
197:
193:
187:
185:
178:
176:
174:
170:
165:
161:
158:
156:
153:, as well as
152:
151:ionic bonding
148:
144:
136:
131:
129:
127:
122:
120:
116:
111:
107:
103:
99:
95:
91:
83:
81:
78:
74:
72:
68:
64:
59:
57:
53:
50:that bind to
49:
45:
41:
40:transcription
37:
33:
19:
1179:
895:
891:
867:
798:
708:
565:
561:
394:
380:
374:
363:
357:
350:
342:
336:
313:
289:
280:
276:
268:
259:
250:
242:
226:
222:coactivators
219:
212:
203:
194:
191:
182:
166:
162:
159:
140:
123:
87:
79:
75:
60:
43:
31:
29:
1346:Termination
1222:Pribnow box
1190:Corepressor
1185:Coactivator
986:prokaryotic
300:acetylation
230:nucleosomes
200:Prokaryotes
188:Recruitment
106:zinc finger
1374:Rho factor
1364:Terminator
1355:eukaryotic
1330:eukaryotic
1311:Elongation
1297:Eukaryotic
1285:Initiation
1068:nucleosome
1051:eukaryotic
1023:gal operon
1018:ara operon
1013:Gua Operon
1008:gab operon
1003:trp operon
998:lac operon
969:Eukaryotic
464:References
453:Squelching
209:Eukaryotes
1350:bacterial
1318:bacterial
1292:Bacterial
1266:Insulator
1210:Promotion
1180:Activator
1030:Repressor
965:Bacterial
912:0022-2836
818:958205447
728:887605755
582:1674-8018
448:Repressor
261:signals.
215:cofactors
119:glutamine
84:Structure
52:enhancers
32:activator
1389:Category
1271:Silencer
1249:Enhancer
1237:CAAT box
1227:TATA box
1217:Promoter
920:10550204
600:22180087
402:See also
328:Examples
63:promoter
44:positive
1197:Inducer
1064:histone
591:4712173
339:maltose
310:Synergy
173:introns
117:-rich,
115:alanine
90:domains
993:Operon
918:
910:
816:
806:
726:
716:
598:
588:
580:
433:Operon
377:operon
360:operon
302:, and
169:operon
108:, and
1254:E-box
1106:HDAC1
1325:rpoB
1168:both
1155:CHD7
1086:EZH2
916:PMID
908:ISSN
814:OCLC
804:ISBN
724:OCLC
714:ISBN
596:PMID
578:ISSN
364:The
92:: a
69:and
1232:BRE
900:doi
896:293
586:PMC
570:doi
395:lac
375:lac
358:lac
341:in
54:or
1391::
1335::
1323::
1070:):
967:,
914:.
906:.
894:.
890:.
876:^
866:.
826:^
812:.
736:^
722:.
608:^
594:.
584:.
576:.
564:.
560:.
472:^
383:.
298:,
149:,
104:,
1357:)
1352:,
1348:(
1148::
1125::
1079:/
1066:/
1062:(
971:)
963:(
953:e
946:t
939:v
922:.
902::
820:.
730:.
602:.
572::
566:2
20:)
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