The mouse B cell-specific mb-1 gene encodes an immunoreceptor tyrosine-based activation motif (ITAM) protein that may be evolutionarily conserved in diverse species by purifying selection

Abstract

The B-lymphocyte accessory molecule Ig-alpha (Ig-α) is encoded by the mouse B cell-specific gene (mb-1), and along with the Ig-beta (Ig-β) molecule and a membrane bound immunoglobulin (mIg) makes up the B-cell receptor (BCR). Ig-α and Ig-β form a heterodimer structure that upon antigen binding and receptor clustering primarily initiates and controls BCR intracellular signaling via a phosphorylation cascade, ultimately triggering an effector response. The signaling capacity of Ig-α is contained within its immunoreceptor tyrosine-based activation motif (ITAM), which is also a key component for intracellular signaling initiation in other immune cell-specific receptors. Although numerous studies have been devoted to the mb-1 gene product, Ig-α, and its signaling mechanism, an evolutionary analysis of the mb-1 gene has been lacking until now. In this study, mb-1 coding sequences from 19 species were compared using Bayesian inference. Analysis revealed a gene phylogeny consistent with an expected species divergence pattern, clustering species from the primate order separate from lower mammals and other species. In addition, an overall comparison of non-synonymous and synonymous nucleotide mutational changes suggests that the mb-1 gene has undergone purifying selection throughout its evolution.

The Dm element located in the Igκ locus is hypermethylated in primary RAG- deficient pre-B cells

“…The mb-1 is a B lymphocytes-speci c gene, which encodes the B cell accessory molecule Iga. We chose mb-1 promoter and beta-globin locus control region served as positive and negative controls for DNA demethylation in B cells, respectively [14,15]; kidney genomic DNA was used as a non-lymphoid control (Data not shown) [11]. Bisul te sequence showed that the Dm element exhibits high methylation levels in pre-B cells, with no signi cant difference observed in the expression of RAG2(Fig.…”

Eulophia Gracilis Orchid Profers Mitigative Influence on Benzene-Initiated Onco-Hematologic Toxicities in Male Wistar Rats

“…CD79 is heterodimeric transmembrane protein that is associated with membrane immunoglobulin and expressed in B cell at early stages of its development until the last stage of maturation before differentiation to plasma cells [36]. It has also been found in biphenotypic leukemia cases of myeloid leukemia, where it was coexpressed with myeloid markers on bone marrow blast cells [37].…”

Expression of the B-Cell Receptor Component CD79a on Immature Myeloid Cells Contributes to Their Tumor Promoting Effects

“…CD79a (also known as Ig-α or mb-1) is an integral membrane protein that is highly conserved among many species [16]. It is expressed at the very early stages of B cell development [17], and expression of CD79a is maintained until the last stage of maturation before differentiation to plasma cells [18], [19].…”