Fig 2: Detection of matriglycan on HAP1-DAG1- cells by flow cytometry.a CMP-Neu5Ac’s modified with defined matriglycan polymeric repeats (100 µM) are engineered on HAP1-DAG1- cells using ST6GAL1 in the presence of C. perfringens neuraminidase. b Detection of matriglycan with 1, 4, 5, and 6 disaccharide repeats on HAP1-DAG1- cells by flow cytometry. Cells were stained with avidin-AF488 and co-stained with PI to exclude non-viable cells. c Detection of matriglycan with 4 repeats at various concentrations of modified donor. d Binding of IIH6 to HAP1-WT and HAP1-DAG1- matriglycan modified cells. e Shotgun proteomics analysis of proteins immunoprecipitated from HAP1-DAG1- cells labeled with Biotin or Biotin+8 disaccharide repeats. Proteins present in the negative control experiment (unlabelled cells), had fewer than 10 spectral counts in the CMP-Neu5Ac-(Biotin) labeling experiment, or known to be localized in intracellular compartments as assessed by UNIPROT annotations, were excluded. Proteins shown are all annotated in UNIPROT to contain sites of N-glycosylation or were manually validated to contain at least one N-X-(S/T) N-glycosylation sequon in the primary sequence. One representative run is shown. Three independent experiments were performed with similar results each time. Source data are provided as a Source Data file.

Fig 3: Cell Surface Glycan Engineering of matriglycan rescues LASV-pseudovirus infection in dystroglycan-deficient cells.Matriglycan engineered HAP1-DAG1- cells, and unlabeled DAG1- and WT controls were incubated for 1 h with rVSV-?G-LASV (MOI 1), then washed and incubated for 24 h before quantifying infectivity. a Fluorescence microscopy of eGFP-positive cells 24 h post infection. Three independent experiments were performed with similar results each time. Scale bars represent 500 µm. Also shown are cartoon representations of the glycan structures presented at the surface of indicated cells. b Quantification of GFP-positive cells using a Nexcelom Cellometer. c LASV-pseudovirus infection of cells lacking the classical O-mannosylation pathway (deficient in POMT2), can also be restored by matriglycan labeling with 6 disaccharide repeats. For b, c measurements were taken at n = 3 independent experiments, where bars represent the mean and error bars represent SD. Source data of b, c are provided as a Source Data file.