Assembly and characterization of heterochromatin and euchromatin on human artificial chromosomes

Table 3 Replication timing of artificial chromosomes

	Artificial chromosomes		Replication timing
			Early: 0-2 h S		Mid: 2-4 h S		Mid: 4-6 h S		Late: 6-8 h S
Line	Chromatin composition*	Replication timing^†	L	U	L	U	L	U	L	U
17-E29	Euchromatin	Early/mid	15	10	4	15	1	29	0	26
17-D34	Euchromatin	Early/mid	16	11	26	13	0	31	0	32
17-B12	Euchromatin/heterochromatin	Mid	2	24	14	15	9	19	0	30
17-C20	Euchromatin/heterochromatin	Mid	0	56	20	57	0	57	0	57
Controls
17 cen	Heterochromatin	Mid	5	182	27	166	46	209	7	236
Yq	Heterochromatin	Mid/late	0	138	1	166	70	116	118	81

The number of either labeled (L) or unlabeled (U) artificial chromosomes in lines 17-E29, 17-D34, 17-B12 or 17-C20 or host control 17 centromere regions (17 cen) or Y long arm sequences (Yq) following BrdU detection at 2 h intervals in S phase is indicated in columns early, mid or late S phase. *Chromatin composition of artificial chromosomes in the four lines indicated or control host 17 centromere or Yq regions (see Table 2). Euchromatin: euchromatin present; heterochromatin depleted. Euchromatin/heterochromatin: both euchromatin and heterochromatin present. Heterochromatin: predominantly heterochromatin; euchromatin depleted. ^†Predominant phase in S phase during which replication occurs: early/mid: first half (0-4 h) of S phase; mid S phase (2-6 h into S phase); mid to late S (4-8 h into S phase). Pooled data from all experiments were used to generate the numbers for the controls.

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