The predicted 219-amino acid human protein is 85% identical to the avian protein. PX19 contains 2 alpha helices with amphipathic domains in opposite orientation, and the LEA motifs (A/TAEKAK) are clustered within this region.
Northern blot analysis detected 1.0- and 1.2-kb transcripts predominantly in fetal liver, with much lower levels in other fetal tissues. Expression was significantly reduced in adult liver, but was higher in other adult organs. Expression was low in bone marrow and thymus, but high in adult spleen, lymph node, and peripheral blood leukocytes. Further analysis of B-cell lines indicated that expression was higher in mature B cells, predominantly from germinal centers, and absent in progenitor and precursor B-cell lines.