Effect of mild heat-shock stress on human RDM1 gene expression. (A) Semiquantitative analysis of the cDNA expression pattern of the long N-terminal RDM1 isoforms in control and heat-shocked HEK293T cells. (B) Heat-shock inducible upregulation of RDM1ζ. Specific PCR amplification was carried out using the primer pair EV041 (containing the ATG) and EV305 (which overlaps the junction between exon 3 and 7) to produce a diagnostic band of 422 n. (C) cDNA expression pattern of the short N-terminal RDM1 isoforms in control and heat-shocked MCF7 cells, illustrating the downregulation of ΔN-RDM1α, -β, -γ, and -ε, and the upregulation of ΔN-RDM1ζ in response to heat shock. RNA isolation and semiquantitative RT-PCR analyses were carried out as described under ‘Materials and Methods’. Primers EV041 and EV042 (long N-terminal isoforms), EV254 and EV042 (short N-terminal isoforms) were used in the reactions, together with primers for β-actin as internal control (see Supplementary Table 1). C, control; HS, heat shock; M, molecular weight markers. See text for details.