<i>Rbm46</i> expression is restricted to spermatogonia, spermatocytes, and early round spermatids in the adult testis.

(A) Violin plots showing relative mRNA levels from single cell (sc)RNA-seq data from adult mouse testes [4]. Undiff = undifferentiated; diff = differentiating; spg = spermatogonia; lep/zyg = leptotene + zygotene; pach = pachytene; spc = spermatocyte; tid = spermatid; MΦ = macrophage; PV = perivascular; PTM = peritubular myoid. (B) Diagram depicting insertion of the 2x FLAG tag upstream of exon 2 of the genomic Rbm46 locus. (C-G) IIF was performed to localize the RBM46-FLAG (green in C, red in D-G) in testes from adult Rbm46FLAG/FLAG mice. (C) RBM46-FLAG (green) was detectable in germ cells but not in GATA4+ (red) Sertoli cells. (D-G) RBM46-FLAG (red) was faintly detectable in ZBTB16+ (green) undifferentiated spermatogonia and KIT+ (green) differentiating spermatogonia, indicated by white arrows. Insets in D-E are single fluorescent channel images of individual ZBTB16+ undifferentiated and chains of KIT+ differentiating spermatogonia (in white), respectively. RBM46-FLAG (red) became readily detectable in SYCP3+ (green) spermatocytes (white arrows = pachytene, yellow = leptotene) and was undetectable in lectin+ (green) spermatids (white arrows). Nuclei were stained with DAPI (blue). Scale bars = 25 μm.