Table I. Differential expression of nuclear genes in mtDNA-depleted C2C12 cells.

Genes identified	mRNA levels (fold of control cells)
	Depleted	Reverted
RyR1	18.0	3.0
Calsequestrin	4.1	1.1
Calreticulin	2.5	1.2
Cathepsin L	5.0	2.0
Mouse melanoma antigen	16.0	2.5
PEP carboxykinase	3.0	1.5
Two novel genes with no     homology to published sequence	4.0–5.3	2.0–3.0
TGFβ1	5.0	1.1
Insulin receptor substrate 1	0.5	0.7
mtDNA transcripts	0.2	0.7–0.9

Primer extension products showing increased or decreased RNA levels in mtDNA-depleted cells were PCR amplified and sequenced to determine the identity of genes. The DNA fragments were also used as probes in northern blot hybridization with RNA from control, depleted and reverted cells. The RNA levels are expressed as fold of control cell level, considered to be 1.