Table I. Characteristics of HCMV- and IE2-induced cell cycle phenotypes.

Cell cycle parameter	HCMV-arrested cells		IE2-arrested cellsa
	Compared with		Compared with
	Quiescent	Cycling	p16-arrested	Cycling
Rb phosphorylation	++a,b	+a,b	++	0
cycE activity	++a,b,c	++a,b,c	++	+
cycA activity	0a,b,c	–a,b,c	+	–
cycB activity	++a,b	+a,b	++	0
E2F-induced transcription	++d	+d	++	0
PCNA expression	++e		++

++, strongly increased; +, increased; 0, unchanged; -, reduced; –, strongly reduced.

The cell cycle state of cells arrested by HCMV infection is compared with proliferating cells (cycling) and with cells arrested by growth factor withdrawal or contact inhibition (quiescent). References b–e have used primary fibroblasts.

^aThis study.

^bJault et al. (1995).

^cBresnahan et al. (1996).

^dWade et al. (1992).

^eDittmer and Mocarski (1997).