By using the partially conserved axial-vector current hypothesis and the electromagnetic current conservation law, we calculate transverse and longitudinal multipoles for threshold pion electroproduction on the nucleon. We include off-shell form factors for the axial-vector current, the electromagnetic current, and the pion-nucleon vertex. We confirm that if the electromagnetic off-shell form factors are assumed to be finite in the chiral limit of the vanishing pion mass, the low-energy theorems are unaffected by them. However, we show that if one of these form factors has simple-pole singularity in the chiral limit, it shows up in the threshold amplitudes at next-to-leading order predicted by the low-energy theorems.