MS4a4B mRNA is expressed in mouse tissues and cells. (A) Northern blot: 10 μg RNA was separated on 1% denatured agarose gel and transferred to membrane, probed using Ms4a4b or G3PDH probes, washed, and exposed overnight. The length of the transcript is shown. (B) RT-PCR: samples were normalized by HPRT PCR and then were amplified with the primers specific for Ms4a4b, separated by gel, stained with ethidium bromide, and photographed. Samples were IL-2-expanded NK cells from severe combined immunodeficient (SCID) bone marrow, WEHI-231 B cells, Mel-201 erythroid line, J774 macrophage line, and 70Z-13 pre-B-cell line. (C) Quantitative PCR for expression of Ms4a4b, Ms4a4c, and Ms4a4d was performed using the Light-Cycler system (see “Materials and methods”). Results are in arbitrary units normalized to HPRT, and ribosomal RNA standards were done in parallel. Results shown are representative of 2 experiments. Samples are (1) expanded primary NK cells, (2) bone marrow, (3) whole spleen, (4) kidney, (5) pre-B-cell line 70Z13, (6) brain, (7) liver, (8) lung, (9) macrophage line (J774) FACS-sorted cells, (10) CD4 SP (single-positive thymocytes), (11) spleen T cells (CD3⁺), (12) spleen NK cells (NK1.1⁺), and (13) macrophages (Mac1⁺). (D) Alignments of deduced amino acid sequences for the mouse Ms4a4 subfamily, Ms4a1 (CD20), and Ms4a2 (FcϵRIβ). The membrane-spanning domains (TM) are predicted by TMHMM 2.0 program and underlined. Identical sequences are indicated by bold letters in light shade; conservative sequences by unshaded letters; nonhomologous sequences by dark shade. ITAM motif in cytoplasmic domain of MS4a2 is indicated as italic.