Protocol for simultaneous detection of mRNAs and (phospho-)proteins with ARTseq-FISH in mouse embryonic stem cells

Understanding the molecular signatures of individual cells within complex biological systems is crucial for deciphering cellular heterogeneity and uncovering regulatory mechanisms. Here, we present a protocol for simultaneous multiplexed detection of selected mRNAs and (phospho-)proteins in mouse embryonic stem cells using spatial single-cell profiling. We describe steps for employing single-stranded DNA (ssDNA)-labeled antibo'dies, padlock probes, and rolling circle amplification to achieve simultaneous visualization of mRNAs and (phospho-)proteins at subcellular resolution. This protocol has potential application in identifying cells in heterogeneous biological microenvironments. For complete details on the use and execution of this protocol, please refer to Hu et al.¹.