Differential B cell expression of mouse Fc receptor homologs.
Five Fc receptor homologs (FcRH1-5) possessing inhibitory and/or activating signaling motifs are differentially expressed during B cell differentiation in humans. In this analysis we describe their three mouse orthologs, moFcRH1, moFcRH2 and moFcRH3. The moFcRH genes are located in a chromosome 3 region that is syntenic with the FcRH locus on human chromosome 1. They encode proteins with 2-5 Ig-like domains that share 20-61% extracellular identity with their human counterparts. One moFcRH1 isoform lacks a transmembrane domain as do both moFcRH2 isoforms. The other moFcRH1 isoform and two moFcRH3 isoforms have transmembrane domains and cytoplasmic ITIM and ITAM-like consensus sequences implying their inhibitory or activating signaling potential. Whereas the moFcRH1 and moFcRH3 orthologs are preferentially expressed at different stages in B cell differentiation, the structurally novel moFcRH2 gene is expressed in non-lymphoid tissues. The highly restricted pattern of moFcRH3 expression suggests this member of the phylogenetically conserved FcRH family may have an important immunoregulatory role in marginal zone B cells.
Division of Developmental and Clinical Immunology, University of Alabama at Birmingham, 35294-3300, USA.
Randall S
RS
Davis
Robert P
RP
Stephan
Ching-Cheng
CC
Chen
Glynn
G
Dennis
Max D
MD
Cooper
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D019070:Cell Lineage; D002874:Chromosome Mapping; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011961:Receptors, Fc / Q000737:chemistry / Q000235:genetics* / Q000502:physiology
D011961:Receptors, Fc