Patent ID: 8211637

Claim:
A process for preparing a sample containing RNA for in situ analysis of RNA or a surrogate thereof, the process comprising: contacting the sample containing RNA with a lysis mixture under conditions and for a time to produce a lysate, wherein the lysis mixture comprises: proteinase K or an enzymatically active mutant or variant thereof, a polypeptide having deoxyribonuclease activity, and a surfactant that substantially lacks fluorescence between 300 nm and 750 nm when in use for in situ analysis of RNA or a surrogate thereof, wherein the lysis mixture is substantially free of a cation chelator; and admixing the lysate with a stop mixture at substantially the same temperature as the contacting step to form a stopped mixture, wherein the stop mixture comprises: a cation chelator effective to inactivate the polypeptide having deoxyribonuclease activity, and at least one alkoxysuccinyl-peptidyl-haloalkyl ketone wherein the peptidyl portion of the ketone comprises SEQ ID NO:5; wherein the halo of haloalkyl is mono- or di-chloro, bromo, or iodo and the alkyl of haloalkyl or alkoxy is C 1 -C 3 alkyl, and wherein the stopped mixture is thereby prepared for in situ analysis of RNA or a surrogate thereof.