Polycystin-1 and polycystin-2, encoded by the PKD1 (OMIM 601313) and PKD2 (OMIM 173910) genes, respectively, are mutated in the majority of patients with autosomal dominant polycystic kidney disease Sequence analysis predicted that PKD2L2 has 6 to 8 transmembrane domains, 2 cation channel motifs, and a channel pore calcium sodium motif. In contrast to PKD2, it has no putative EF-hand or coiled-coil domains. By Northern blot and RT-PCR analyses, expression of approximately 1.2-, 1.5-, and 2.5-kb PKD2L2 transcripts in testis only.
General function
Channel/transport protein
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Cellular localization
Plasma membrane
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Ovarian function
Oogenesis
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Expression regulated by
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Ovarian localization
Oocyte
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Proteins of the polycystin (PKD) family interact to form calcium-permeable channels and are presumed ion channel regulators. These genes are important to proper functioning of the kidney; mutations result in polycystic kidney disease. Because no other functions for polycystin family members has appeared, a first assumption would be that PKD2L2 protein is also involved in calcium channel formation. Such a function is anticipated because intracellular calcium plays important roles in oocyte and egg biology. Intracellular calcium is released during germinal vesicle breakdown as meiosis resumes and at fertilization as the sperm and egg membranes fuse. The finding of a calcium channel protein in the oocyte is important because it suggests that the polycystin family of ion channels may play a role in calcium events during oocyte development Robert A. Taft et al 2002 .
Follicle stages
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Genomewide discovery and classification of candidate ovarian fertility genes in the mouse. Gallardo TD et al. Female infertility syndromes are among the most prevalent chronic health disorders in women, but their genetic basis remains unknown because of uncertainty regarding the number and identity of ovarian factors controlling the assembly, preservation, and maturation of ovarian follicles. To systematically discover ovarian fertility genes en masse, we employed a mouse model (Foxo3) in which follicles are assembled normally but then undergo synchronous activation. We developed a microarray-based approach for the systematic discovery of tissue-specific genes and, by applying it to Foxo3 ovaries and other samples, defined a surprisingly large set of ovarian factors (n = 348, approximately 1% of the mouse genome). This set included the vast majority of known ovarian factors, 44% of which when mutated produce female sterility phenotypes, but most were novel. Comparative profiling of other tissues, including microdissected oocytes and somatic cells, revealed distinct gene classes and provided new insights into oogenesis and ovarian function, demonstrating the utility of our approach for tissue-specific gene discovery. This study will thus facilitate comprehensive analyses of follicle development, ovarian function, and female infertility. This is an oocyte-specific gene.