Gene Map Locus: 7q11.23
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During the process of fertilization, the initial interaction
between male and female gametes is mediated by a sperm receptor,
designated ZP3, which resides in the extracellular glycoprotein
matrix (zona pellucida) surrounding the oocyte. The sperm receptor
function of the ZP3 molecule plays a key role in the first step of
the fertilization process. Following sperm-oocyte binding, ZP3
triggers the sperm acrosome reaction that releases the protein
machinery enabling a spermatozoon to penetrate the zona pellucida. By
analysis of a rodent-human somatic cell hybrid panel, van
Duin et al. (1991) and van Duin et al.
(1993) mapped the ZP3 gene to chromosome 7. Dean
(1992) reviewed the molecular biology of mammalian fertilization
with particular reference to the ZP glycoproteins. He compared the
structure of the mouse and human ZP2 (182888)
and ZP3 genes and pointed out that the use of embryonic stem cell
technology in animal models with null mutations in the ZP genes will
define the phenotypes of genetic defects and facilitate the search
for their human counterparts. Lunsford et al.
(1990) demonstrated that the mouse Zp-2 and Zp-3 genes are
located on chromosomes 7 and 5, respectively.
Genomic and cDNA cloning by van Duin et al.
(1992) demonstrated that the ZP3 gene has 8 exons, spread over 18
kb, encoding a protein of 424 amino acids with a 67% homology to
mouse and hamster ZP3. By Southern blotting, gene cloning, and
sequence analysis, van Duin et al. (1992)
demonstrated that the human genome contains a second polymorphic
locus which, due to an extra G residue in exon 8, has the potential
to encode a truncated protein of 372 amino acids. Direct sequence
analysis of PCR-amplified exon 8 DNA of 56 persons from various
populations demonstrated 3 different sequence patterns: 1 containing
only ZP3-424-coding sequences and 2 containing ZP3-424- and
ZP3-372-coding DNA. The distribution of these 3 patterns was
significantly different between the Caucasian and Japanese
populations, as indicated by ZP3-372 allele frequencies of 69 and
21%, respectively. Isolation of ZP3-424 and ZP3-372 cDNAs suggested
that both loci represent functional transcription units. Thus, during
oogenesis, ZP3 appears to be translated from mRNAs derived from 2 to
4 transcription units. Provided that ZP3-372 mRNA is translated in
vivo, differences in the protein gene product might have an impact on
human zona pellucida composition.
By fluorescence in situ hybridization, Kipersztok et al. (1995) mapped the ZP3A gene to 7q11.23.
See ZP3B (195002).
Patti M. Sherman - updated : 2/20/1998
Victor A. McKusick : 8/6/1991
psherman : 6/25/1998
dholmes : 2/20/1998
dholmes : 2/20/1998
mark : 6/12/1997
mark : 6/12/1997
carol : 1/8/1993
carol : 7/24/1992
supermim : 3/16/1992
carol : 2/23/1992
carol : 8/30/1991
carol : 8/20/1991