MOLECULAR-CLONING OF A HUMAN RP105 HOMOLOG AND CHROMOSOMAL LOCALIZATION OF THE MOUSE AND HUMAN RP105 GENES (LY64 AND LY64)

RP105 is a mouse B cell surface molecule that transmits a growth-promo ting signal and is implicated in the life/death decision of B cells. R P105 has tandem repeats of a leucine-rich motif in the extracellular d omain that is expected to be involved in protein-protein interactions. In the present study, a cDNA clone encoding the human homologue of RP 105 was isolated. The amino acid sequence of human RP105 is highly hom ologous to that of mouse RP105 with 74% identity, and the leucine-rich repeats are well conserved. The expression of the human RP105 transcr ipt was detected in some B cell lines, a histiocytic leukemia cell lin e, and peripheral blood leukocytes. We also determined the chromosomal locations of the mouse RP105 gene (Ly64 locus) and the human RP105 ge ne (LY64 locus). Interspecific mouse backcross analysis was used to ma p the Ly64 locus at the distal region of chromosome 13. The human LY64 locus was localized to 5q12 by fluorescence in situ hybridization, co nfirming the syntenic relationship between these regions of the mouse and human chromosomes. (C) 1996 Academic Press, Inc.