Disclosed herein include methods, compositions, and kits suitable for use in signal amplification. There are provided, in some embodiments, protease-based signal amplification modules. Disclosed herein include amplifier proteins comprising a first part of a first protease domain, a first dimerization domain, a first cut site a protease in a protease active state is capable of cutting, a second dimerization domain, a second cut site a protease in a protease active state is capable of cutting, and a first caging domain. Disclosed herein include companion amplifier proteins comprising a second part of a first protease domain, a third dimerization domain, a third cut site a protease in a protease active state is capable of cutting, a fourth dimerization domain, a fourth cut site a protease in a protease active state is capable of cutting, and a second caging domain.

Provided is a new-type cis-replicon construct for efficiently expressing a target protein, which comprises an RNA polymerase coding unit and a target protein coding unit. The replicon construct can drive the replication of the target protein coding unit and reduce or avoid the replication and expression of the RNA polymerase, thereby effectively improving the expression of the target protein and reducing the expression of the non-target protein.