(A) Top: schematic representation of human SCRIB tv1: light gray arrow, 5′ and 3′ UTR; dark gray arrow, SCRIB coding sequence; red arrow, smORF encoding EMBOW. Bottom: the cDNA sequence of human SCRIB tv1 is shown with the protein sequences of EMBOW (bold) and SCRIB indicated below. The start codons of EMBOW (black) and SCRIB (blue) and the stop codon of EMBOW (black) are numbered. Highlighted in red is the tryptic peptide of EMBOW detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS).
(B and C) MS/MS spectra of EMBOW tryptic peptide detected in HT1080 and primary cultured melanoma cells (YUZEST). Mascot score, precursor mass error and precursor charge state are presented.
(D) Control (293T) or EMBOW-FLAG-HA knockin (KI) HEK293T cells were transiently transfected with a plasmid encoding alt-C1orf122-FLAG,25 serving as an FLAG-IP positive control, and IPs were performed followed by immunoblotting (IB). Cell lysates (4%) before IP (input) were used as the loading controls. Data are representative of three biological replicates.
(E) Immunostaining of two independent EMBOW-FLAG-HA KI cell lines (KI-1 and KI-2) and HEK293T cells (293T) as a negative control with anti-FLAG (red) and DAPI (cyan). Scale bars, 10 μm. Data are representative of three biological replicates.
See also Figure S1.