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Identification of a new murine eosinophil major basic protein (mMBP) gene: cloning and characterization of mMBP‐2
Author(s) -
Macias MiMi P.,
Welch Kenneth C.,
Denzler Karen L.,
Larson Kirsten A.,
Lee Nancy A.,
Lee James J.
Publication year - 2000
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.67.4.567
Subject(s) - biology , microbiology and biotechnology , gene , open reading frame , gene family , complementary dna , genetics , gene expression , peptide sequence
We have identified a new eosinophil major basic protein gene family member in the mouse and have given it the designation murine major basic protein‐2 (mMBP‐2). The gene was initially characterized as a unique expressed sequence tag (EST) clone having significant identity to the previously recognized member of this gene family, mMBP‐1. The EST was used to screen and isolate mMBP‐2 from a bone marrow cDNA library. In addition, a genomic clone of mMBP‐2 was isolated and this gene was shown to be physically linked to within 100 kb of mMBP‐1 on the central region of mouse chromosome 2. Progressive similarity alignment of the deduced mMBP‐2 open reading frame demonstrates the apparent conservation of the “pre‐pro‐mature” protein structure found in the other known mammalian MBPs. Mature mMBP‐2 maintains the cationic nature associated with these proteins with a predicted pI of 9.95. However, unlike the human MBPs, which display a three orders of magnitude charge difference [hMBP‐1 (p I 11.4) vs. hMBP‐2 (p I 8.7)], mMBP‐2 is only slightly less cationic than mMBP‐1 (p I 10.5). Expression studies demonstrate that transcription of the mMBP‐2 gene parallels mMBP‐1 and is confined to hematopoietic compartments engaged in eosinophilopoiesis. Moreover, using mMBP‐1 knockout mice and immunohistochemistry with an antisera that recognizes both mMBP‐1 and ‐2, we demonstrate that mMBP‐2 protein expression is restricted to eosinophil lineage‐committed cells. J. Leukoc. Biol. 67: 567–576; 2000.