Expression of Kell blood group protein in nonerythroid tissues.
The Kell blood group protein is a zinc endopeptidase that yields endothelin-3, a potent bioactive peptide, by cleavage of big endothelin-3, a larger intermediate precursor. On red cells, Kell protein is linked by a single disulfide bond to XK, a protein that traverses the membrane 10 times and whose absence, as occurs in the McLeod phenotype, is associated with a set of clinical symptoms that include nerve and muscle disorders and red cell acanthocytosis. Previous studies indicated that Kell is primarily expressed in erythroid tissues, whereas XK has a wider tissue distribution. The tissue distribution of Kell protein has been further investigated by Northern blot analysis, PCR-screening of tissue complementary DNAs (cDNAs), and Western immunoblots. Screening of an RNA dot-blot panel confirmed that Kell is primarily expressed in erythroid tissues but is also expressed in a near equal amount in testis, with weaker expression in a large number of other tissues. PCR-screening of cDNAs from different tissues and DNA sequencing of the products gave similar results. In 2 of the nonerythroid tissues tested, testis and skeletal muscle, Kell protein was detected by Western immunoblotting. In skeletal muscle, isolation of XK with a specific antibody coisolated Kell protein. These studies demonstrate that Kell is expressed in both erythroid and nonerythroid tissues and is associated with XK.
Russo
D
D
Lindsley F. Kimball Research Institute, The New York Blood Center, New York, New York 10021, USA.
Wu
X
X
Redman
C M
CM
Lee
S
S
D026921:Amino Acid Transport Systems, Neutral; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D017931:DNA Primers; D018076:DNA, Complementary; D005091:Exons; D005260:Female; D015723:Gene Library; D007626:Kell Blood-Group System / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D018482:Muscle, Skeletal / Q000378:metabolism*; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D013737:Testis / Q000378:metabolism
D026921:Amino Acid Transport Systems, Neutral; D002352:Carrier Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D007626:Kell Blood-Group System; D008565:Membrane Proteins; C498286:Xkh protein, mouse