It is not surprising that a large number of diseases related to amyloid fibril depositions are formed in various organs. Therefore, it is necessary to understand the transformation of native proteins into amyloid fibrils in order to clarify which key elements of this process determine the pathway of protein misfolding. Significant attention has been directed recently to investigating the mechanism of formation of cross-β structures that have the properties of liquids but can also exist in gel-like forms, thus facilitating the retention of both RNAs and RNA-binding proteins. Proteins that form stress granules are believed to do this rapidly, and they are expected to contain a prion-like domain that can facilitate this process. By analyzing the known yeast prion proteins and 29 RNA-binding proteins with prion-like domains, we demonstrate here that the existence of repeats is one of the general characteristics of prion-like domains. The presence of repeats should help to determine the border of prion domains as in the case of Rnq1: five found repeats shift the border of the prion domain from the 153-rd to at least the 133-th residue. One can suggest that such repeats assist in the rapid initiation of the process of assembly and formation of cross-β structures and such domains most likely should be disordered. These repeats should contain aromatic amino acid residues for the formation of a hydrogel because its amino acid context modulates the strength of interaction. The key factors determined here can be used to control the process of aggregation to prevent the development of pathologies and diseases caused by prion-like domains.