0	10	Regulation	regulation	NN
11	13	of	of	IN
14	17	Id3	id3	NN
18	22	cell	cell	NN
23	28	cycle	cycle	NN
29	37	function	function	NN
38	40	by	by	IN
41	56	Cdk-2-dependent	cdk-2-dependent	JJ
57	72	phosphorylation	phosphorylation	NN
72	73	.	.	.

75	78	The	the	DT
79	88	functions	function	NNS
89	91	of	of	IN
92	97	basic	basic	JJ
98	114	helix-loop-helix	helix-loop-helix	JJ
115	116	(	(	(
116	120	bHLH	bhlh	JJ
120	121	)	)	)
122	135	transcription	transcription	NN
136	143	factors	factor	NNS
144	146	in	in	IN
147	157	activating	activate	VBG
158	180	differentiation-linked	differentiation-linked	JJ
181	185	gene	gene	NN
186	196	expression	expression	NN
197	200	and	and	CC
201	203	in	in	IN
204	212	inducing	induce	VBG
213	215	G1	g1	NN
216	220	cell	cell	NN
221	226	cycle	cycle	NN
227	233	arrest	arrest	NN
234	237	are	be	VBP
238	248	negatively	negatively	RB
249	258	regulated	regulate	VBN
259	261	by	by	IN
262	269	members	member	NNS
270	272	of	of	IN
273	276	the	the	DT
277	279	Id	id	NN
280	286	family	family	NN
287	289	of	of	IN
290	293	HLH	hlh	JJ
294	302	proteins	protein	NNS
302	303	.	.	.

304	309	These	these	DT
310	314	bHLH	bhlh	JJ
315	326	antagonists	antagonist	NNS
327	330	are	be	VBP
331	338	induced	induce	VBN
339	345	during	during	IN
346	347	a	a	DT
348	357	mitogenic	mitogenic	JJ
358	368	signalling	signalling	NN
369	377	response	response	NN
377	378	,	,	,
379	382	and	and	CC
383	387	they	they	PRP
388	396	function	function	VBP
397	399	by	by	IN
400	412	sequestering	sequester	VBG
413	418	their	their	PRP$
419	423	bHLH	bhlh	JJ
424	431	targets	target	NNS
432	434	in	in	IN
435	443	inactive	inactive	JJ
444	456	heterodimers	heterodimer	NNS
457	461	that	that	WDT
462	465	are	be	VBP
466	472	unable	unable	JJ
473	475	to	to	TO
476	480	bind	bind	VB
481	483	to	to	TO
484	492	specific	specific	JJ
493	497	gene	gene	NN
498	508	regulatory	regulatory	JJ
509	510	(	(	(
510	511	E	e	NN
512	515	box	box	NN
515	516	)	)	)
517	526	sequences	sequence	NNS
526	527	.	.	.

528	536	Recently	recently	RB
536	537	,	,	,
538	544	cyclin	cyclin	NN
545	552	E-Cdk2-	e-cdk2-	NN
553	556	and	and	CC
557	563	cyclin	cyclin	NN
564	580	A-Cdk2-dependent	a-cdk2-dependent	JJ
581	596	phosphorylation	phosphorylation	NN
597	599	of	of	IN
600	601	a	a	DT
602	608	single	single	JJ
609	618	conserved	conserve	VBN
619	625	serine	serine	NN
626	633	residue	residue	NN
634	635	(	(	(
635	639	Ser5	Ser5	NNP
639	640	)	)	)
641	643	in	in	IN
644	647	Id2	id2	NN
648	651	has	have	VBZ
652	656	been	be	VBN
657	662	shown	show	VBN
663	665	to	to	TO
666	671	occur	occur	VB
672	678	during	during	IN
679	683	late	late	JJ
684	691	G1-to-S	g1-to-s	JJ
692	697	phase	phase	NN
698	708	transition	transition	NN
709	711	of	of	IN
712	715	the	the	DT
716	720	cell	cell	NN
721	726	cycle	cycle	NN
726	727	,	,	,
728	731	and	and	CC
732	736	this	this	DT
737	748	neutralizes	neutralize	VBZ
749	752	the	the	DT
753	761	function	function	NN
762	764	of	of	IN
765	768	Id2	id2	NN
769	771	in	in	IN
772	782	abrogating	abrogate	VBG
783	798	E-box-dependent	e-box-dependent	JJ
799	803	bHLH	bhlh	JJ
804	809	homo-	homo-	JJ
810	812	or	or	CC
813	824	heterodimer	heterodimer	NN
825	832	complex	complex	NN
833	842	formation	formation	NN
843	845	in	in	FW
846	851	vitro	vitro	FW
852	853	(	(	(
853	859	E.Hara	E.Hara	NNP
859	860	,	,	,
861	867	M.Hall	M.Hall	NNP
867	868	,	,	,
869	872	and	and	CC
873	881	G.Peters	G.Peters	NNP
881	882	,	,	,
883	887	EMBO	EMBO	NNP
888	900	J.16:332-342	J.16:332-342	NNP
900	901	,	,	,
902	906	1997	1997	CD
906	907	)	)	)
907	908	.	.	.

909	911	We	we	PRP
912	915	now	now	RB
916	920	show	show	VBP
921	925	that	that	IN
926	928	an	an	DT
929	938	analogous	analogous	JJ
939	959	cell-cycle-regulated	cell-cycle-regulated	JJ
960	975	phosphorylation	phosphorylation	NN
976	978	of	of	IN
979	982	Id3	Id3	NNP
983	989	alters	alter	VBZ
990	993	the	the	DT
994	1005	specificity	specificity	NN
1006	1008	of	of	IN
1009	1012	Id3	id3	NN
1013	1016	for	for	IN
1017	1027	abrogating	abrogate	VBG
1028	1032	both	both	CC
1033	1048	E-box-dependent	e-box-dependent	JJ
1049	1053	bHLH	bhlh	JJ
1054	1059	homo-	homo-	NN
1060	1062	or	or	CC
1063	1074	heterodimer	heterodimer	NN
1075	1082	complex	complex	NN
1083	1092	formation	formation	NN
1093	1095	in	in	FW
1096	1101	vitro	vitro	FW
1102	1105	and	and	CC
1106	1121	E-box-dependent	e-box-dependent	JJ
1122	1130	reporter	reporter	NN
1131	1135	gene	gene	NN
1136	1144	function	function	NN
1145	1147	in	in	FW
1148	1152	vivo	vivo	FW
1152	1153	.	.	.

1154	1165	Furthermore	furthermore	RB
1165	1166	,	,	,
1167	1175	compared	compare	VBN
1176	1180	with	with	IN
1181	1190	wild-type	wild-type	JJ
1191	1194	Id3	id3	NN
1194	1195	,	,	,
1196	1198	an	an	DT
1199	1202	Id3	id3	NN
1203	1207	Asp5	asp5	NN
1208	1214	mutant	mutant	NN
1215	1216	(	(	(
1216	1225	mimicking	mimic	VBG
1226	1241	phosphorylation	phosphorylation	NN
1241	1242	)	)	)
1243	1245	is	be	VBZ
1246	1252	unable	unable	JJ
1253	1255	to	to	TO
1256	1263	promote	promote	VB
1264	1268	cell	cell	NN
1269	1274	cycle	cycle	NN
1275	1276	S	S	NNP
1277	1282	phase	phase	NN
1283	1288	entry	entry	NN
1289	1291	in	in	IN
1292	1303	transfected	transfecte	VBN
1304	1315	fibroblasts	fibroblast	NNS
1315	1316	,	,	,
1317	1324	whereas	whereas	IN
1325	1327	an	an	DT
1328	1331	Id3	id3	NN
1332	1336	Ala5	ala5	NN
1337	1343	mutant	mutant	NN
1344	1345	(	(	(
1345	1353	ablating	ablate	VBG
1354	1369	phosphorylation	phosphorylation	NN
1369	1370	)	)	)
1371	1379	displays	display	VBZ
1380	1382	an	an	DT
1383	1391	activity	activity	NN
1392	1405	significantly	significantly	RB
1406	1413	greater	great	JJR
1414	1418	than	than	IN
1419	1423	that	that	DT
1424	1426	of	of	IN
1427	1436	wild-type	wild-type	JJ
1437	1440	Id3	id3	NN
1441	1448	protein	protein	NN
1448	1449	.	.	.

1450	1464	Cdk2-dependent	cdk2-dependent	JJ
1465	1480	phosphorylation	phosphorylation	NN
1481	1490	therefore	therefore	RB
1491	1499	provides	provide	VBZ
1500	1501	a	a	DT
1502	1508	switch	switch	NN
1509	1515	during	during	IN
1516	1520	late	late	JJ
1521	1528	G1-to-S	g1-to-s	JJ
1529	1534	phase	phase	NN
1535	1539	that	that	IN
1540	1544	both	both	CC
1545	1554	nullifies	nullify	VBZ
1555	1557	an	an	DT
1558	1563	early	early	JJ
1564	1566	G1	g1	NN
1567	1571	cell	cell	NN
1572	1577	cycle	cycle	NN
1578	1588	regulatory	regulatory	JJ
1589	1597	function	function	NN
1598	1600	of	of	IN
1601	1604	Id3	Id3	NNP
1605	1608	and	and	CC
1609	1618	modulates	modulate	VBZ
1619	1622	its	its	PRP$
1623	1629	target	target	NN
1630	1634	bHLH	bhlh	JJ
1635	1646	specificity	specificity	NN
1646	1647	.	.	.

1648	1653	These	these	DT
1654	1658	data	datum	NNS
1659	1663	also	also	RB
1664	1675	demonstrate	demonstrate	VBP
1676	1680	that	that	IN
1681	1684	the	the	DT
1685	1692	ability	ability	NN
1693	1695	of	of	IN
1696	1699	Id3	Id3	NNP
1700	1702	to	to	TO
1703	1710	promote	promote	VB
1711	1715	cell	cell	NN
1716	1721	cycle	cycle	NN
1722	1723	S	S	NNP
1724	1729	phase	phase	NN
1730	1735	entry	entry	NN
1736	1738	is	be	VBZ
1739	1742	not	not	RB
1743	1749	simply	simply	RB
1750	1751	a	a	DT
1752	1760	function	function	NN
1761	1763	of	of	IN
1764	1767	its	its	PRP$
1768	1775	ability	ability	NN
1776	1778	to	to	TO
1779	1787	modulate	modulate	VB
1788	1792	bHLH	bhlh	JJ
1793	1814	heterodimer-dependent	heterodimer-dependent	JJ
1815	1819	gene	gene	NN
1820	1830	expression	expression	NN
1831	1834	and	and	CC
1835	1844	establish	establish	VB
1845	1846	a	a	DT
1847	1859	biologically	biologically	RB
1860	1869	important	important	JJ
1870	1879	mechanism	mechanism	NN
1880	1887	through	through	IN
1888	1893	which	which	WDT
1894	1898	Cdk2	cdk2	NN
1899	1902	and	and	CC
1903	1910	Id-bHLH	id-bhlh	JJ
1911	1920	functions	function	NNS
1921	1924	are	be	VBP
1925	1935	integrated	integrate	VBN
1936	1938	in	in	IN
1939	1942	the	the	DT
1943	1955	coordination	coordination	NN
1956	1958	of	of	IN
1959	1963	cell	cell	NN
1964	1977	proliferation	proliferation	NN
1978	1981	and	and	CC
1982	1997	differentiation	differentiation	NN
1997	1998	.	.	.