ACTB and Infertility: While mice overexpressing a truncated constitutively active HSF1 under the control of a human β-actin promoter fail to overexpress HSF1 in the CNS and the male transgenic mice are infertile,38,39 our HSF1-Tg mice grow and breed normally as WT mice, and exhibit moderate increase in HSF1 mRNA and protein expression in all tissues including the CNS6 and the retina (Fig. 2).