Human POM-ZP3 is a novel bipartite RNA transcript that is derived from
a gene homologous to rat POM121 (a nuclear pore membrane protein) and
ZP3 (a sperm receptor ligand in the zona pellucida). The 5' region is
77% identical to the 5' end of the coding region of rat POM121 and ap
pears to represent a partial duplication of a gene encoding a human ho
mologue of this rodent gene. The 3' end of the POM-ZP3 transcript is 9
9% identical to ZP3 and appears to have arisen from a duplication of t
he last four exons (exons 5-8) of ZP3. Using Northern blots and RT-PCR
, POM-ZP3 transcripts were detected in human ovaries, testes, spleen,
thymus, lymphocytes, prostate, and intestines. The longest open readin
g frame encodes a conceptual protein of 210 amino acids, the first 76
of which are 83% identical to residues 241-315 of rat POM121. The next
125 amino acids are 98% identical to residues 239-363 of the 424-amin
o-acid human ZP3 protein. By fluorescence in situ hybridization, genom
ic fragments of ZP3 and a human homologue of POM121 were localized to
chromosome 7q11.23. Taken together, these data suggest that partial du
plications of human ZP3 and a POM121-like gene have resulted in a fusi
on transcript, POM-ZP3, that is expressed in multiple human tissues. (
C) 1995 Academic Press, Inc.