APP and Alzheimer disease: It follows that since mice possess functional RNA-dependent mRNA amplification machinery, and since the ISR is elicited and RdRp complex is, presumably, assembled in the neurons of the current transgenic animal models of AD, the highly plausible deficiency preventing the operation of the AβPP-independent iAβ production pathway is, as discussed in the following section, the lack of the RdRp-compatible, RNA-dependent amplification-eligible AβPP mRNA.