The gene overexpressed in polycythemia rubra vera, PRV-1, and the gene encoding a neutrophil alloantigen, NB1, are alleles of a single gene, CD177, in chromosome band 19q13.31

Abstract

Background: PRV-1 mRNA is overexpressed by neutrophils from polycythemia vera patients and is homologous to NB1 a gene overexpressed in reactive neutrophilia.

Study design and methods: These investigations were designed to confirm searches of genome databases suggesting that PRV-1 and NB1 are alleles of the same gene, CD177, and confirm a pseudogene adjacent to CD177. Methods included polymerase chain reaction (PCR), cloning, sequencing, and fluorescent hybridization studies.

Results: The coding region of PRV-1 was PCR-amplified from human fetal RNA, cloned, and used to screen the RPCI-11 bacterial artificial chromosome (BAC) library. Five BACs were reactive with the PRV-1 probe. PCR analysis of the BACs with primers encompassing PRV-1 exons, containing four known single-nucleotide polymorphisms, followed by sequencing rendered amplicons identical to PRV-1 in all five BACs. Analysis of all five by restriction digestion yielded fragments possible only if both the gene and the pseudogene are present. End sequencing of the BACs localized them to the same chromosome region. G-banding and fluorescence in situ hybridization at the 400- and 850-band levels of resolution mapped one BAC to chromosome band 19q13.2 and sublocalized the BAC to band 19q13.31, respectively.

Conclusion: PRV-1 and NB1 are alleles of the same gene now referred to as CD177. Changes in CD177 expression may be a marker of increased or decreased myelopoiesis and are therefore an effect of, rather than a cause of, myeloproliferative disorders.