Table 1. A comparison of modified (protocol 1) and unmodified (protocol 2) Myers Lab Protocol [5]) for the isolation of primary epithelial cell chromatin for ChIP.

		Protocol 1 (Modified Protocol)		Protocol 2 (Original Myers Protocol [5])
		Primary Airway	Primary Urogenital	Multiple cell types
Cell Number		1.0×107	1.5×107	2.0×107
Steps of the lysis procedure	1. Trypsin-EDTA incubation (0.25% at room temperature)	✓	✓	✗
	2. Equilibration in detergent-free cell membrane lysis buffer	✓	✓	✗
	3. Cell Membrane (Farnham) Lysis Buffer	✓+0.5% Triton X-100	✓+0.5% Triton X-100	✓
	A) Syringe filtered through a 25-gauge needle (4 times)	✓	✓	✗
	4. Equilibration in detergent-free nuclear lysis buffer	✓	✓	✗
	5. Nuclear Membrane Lysis Buffer	✓	✓	✓
Sonication	- Amplitude	35–40	35–40	Not specified
	- Cycles (25 s ON, 59 s OFF)	16–18	16–18	Not specified

Steps included (✓) or omitted (✗).