ISOLATION OF A CDNA CLONE ENCODING A NOVEL MEMBRANE-PROTEIN EXPRESSEDIN LYMPHOCYTES

By subtractive hybridization using single-stranded phagemids with dire ctional inserts, we isolated a mouse cDNA clone, LSM-1, from temperatu re-sensitive Abelson virus-tranformed immature B cells whose different iation was being induced after the shift from the permissive (35 degre es C) to the non-permissive temperature (39 degrees C). LSM-1, which e ncodes an as yet unknown peptide of 197 amino acids, has a putative si gnal sequence and a trans-membrane region, and is expressed in B- and T-cell lines, in spleen, thymus, and bone marrow of adult mice, and in embryos.