Assembly and characterization of heterochromatin and euchromatin on human artificial chromosomes

Table 2 Chromatin formation on artificial chromosomes

Line	Artificial chromosomes		Heterochromatin		Euchromatin
	Alpha-satellite	Size estimate*	H3 TrimK9/K27	HP1α	H3DimK4	^†CENP-A
17-E29	D17Z1	1-3 Mb	-	(-)	+	+
17-D34	D17Z1	1-3 Mb	-	(-)	+	+
17-B12	D17Z1	3-10 Mb	+	+	+	+
17-C20^‡	D17Z1	3-10 Mb	+	+	+	+
X-4	DXZ1	10-20 Mb	+	ND	+	ND
X-5	DXZ1	10-20 Mb	+	ND	+	ND
Host controls
17 cen			+	+	-	+
X cen			+	ND	-	+

Summary of results obtained by immunofluorescence staining on metaphase chromosomes containing artificial chromosomes using antibodies to either heterochromatin (H3TrimK9/K27; HP1α) or euchromatin (H3DimK4) components (Figures 1-3). + positive staining; - signal not detectable; (-) weak staining comparable to general arm staining; ND, not done. *Comparison of alpha satellite signal intensities (using FISH analyses) on the artificial chromosomes with those of the relevant host centromere regions was used to estimate artificial chromosome sizes. ^†CENP-A stains uniformly on artificial chromosomes and at a level comparable to the host staining level [12]. Controls, staining pattern at either host 17 or X centromere regions overlapping with D17Z1 or DXZ1 probes (respectively). ^‡17-C20 contains mitotically unstable artificial chromosomes (Table 1).

ISSN: 1474-760X