integrating 10x Surface Markers data

[SBata]

I'm working with 10X scRNASeq data and the Surface Markers data that come with it. I'm having issues integrating the two datasets, I'm following what suggested in the Multimodal Vignette (https://satijalab.org/seurat/v3.0/multimodal_vignette.html). more specifically:

mat <- Read10X(data.dir = matrix_dir)
# mat[[1]] will have RNA and mat[[2]] will have proteins

list_RNA <- CreateSeuratObject(counts = mat[[1]], project = nn, min.cells = 3, min.features = 200)
list_RNA[["percent.mt"]] <- PercentageFeatureSet(list_RNA, pattern = "^MT-")
list_RNA[[nn]] <- nn
list_RNA <- subset(list_RNA, subset = nFeature_RNA > 200 & nFeature_RNA < 2500 & percent.mt < 5)
list_RNA <- NormalizeData(list_RNA, normalization.method = "CLR", scale.factor = 10000, assay = "RNA")
list_RNA <- FindVariableFeatures(list_RNA, selection.method = "vst", nfeatures = 2000)
list_RNA <- ScaleData(list_RNA)

# now to integrate the data:
list_RNA[["Proteins"]] <- CreateAssayObject(mat[[2]])

but I get

Error: Cannot add a different number of cells than already present any suggestions?

[satijalab]

Should be an easy fix - just make sure to add the protein assay before subsetting.