Figure 8. Northern blot analysis of the citrate synthase (CS) mRNA.

Muscle cell cultures were grown for 24 days in the absence (lane 1) of ionophore. Ca²⁺ ionophore A23187 (4 × 10⁻⁷ M) was added for a further 2 days on day 22 (lane 2) or for a further 13 days on day 11 (lane 3) to the cell cultures. Total RNA (20 μg) was isolated from control and ionophore treated cultures, fractionated on a 1.2 % agarose-formaldehyde gel, and transferred to nitrocellulose. The blots were hybridized with the ³²P-labelled 800 bp ClaI-EcoRV fragment of CS cDNA (1 × 10⁶ c.p.m. ml⁻¹) or an rDNA probe from 18S rRNA (1 × 10⁶ c.p.m. ml⁻¹). The positions of 18S rRNA (1.9 kb) and 28S rRNA (4.8 kb) on the ethidium bromide-stained gel are indicated.