 |
||||
| 2007 JASN IMPACT FACTOR 7.111 | HOME AUTHOR INFO EDITORIAL BOARD SUBSCRIBE FEEDBACK ALERTS HELP | |||
| CURRENT ISSUE | ARCHIVES | JASN Express | ONLINE SUBMISSION | |
|
||||
| 2007 JASN IMPACT FACTOR 7.111 | HOME AUTHOR INFO EDITORIAL BOARD SUBSCRIBE FEEDBACK ALERTS HELP | |||
| CURRENT ISSUE | ARCHIVES | JASN Express | ONLINE SUBMISSION | |
BASIC SCIENCE |
Departments of *Medicine and Comparative Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; Laboratory of Mammalian Genes and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; and Department of Medicine, Shanghai Changzheng Hospital, Shanghai, China
Correspondence to Dr. Gregory G. Germino, Johns Hopkins University School of Medicine, Departments of Medicine and Molecular Biology and Genetics, Division of Nephrology, Ross 958, 720 Rutland Avenue, Baltimore, MD 21205. Phone: 410-614-0089; Fax: 410-614-5129; E-mail: ggermino{at}jhmi.edu
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
neo, by crossing to animals that express either the cre or FLPe recombinase, respectively. It is found that Pkd1del2–4 allele functions as a true null, whereas presence or absence of the neomycin gene has no functional effects. It also is shown that somatic loss of Pkd1 results in renal and hepatic cysts. This new line of mice will be invaluable in the study of Pkd1 biology and serve as a powerful new tool that can be used to study the pathogenesis of autosomal dominant polycystic kidney disease. |
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
A number of mouse lines with targeted mutations of either Pkd1 or Pkd2 have been described (4–8). Regardless of which gene is inactivated, the different mouse lines share many common features. Homozygous inactivation of either gene results in bilateral renal cyst formation beginning at approximately embryonic day 15.5 (E15.5; the presence of a vaginal plug being defined as E0.5d) and invariably results in fetal or perinatal demise. In contrast, mice with heterozygous mutations of Pkd1 or Pkd2 are generally normal and have few if any renal cysts, although hepatic cysts often are a late presentation. Although these studies have shown conclusively that Pkd1 and Pkd2 are required for the establishment of normal renal tubular morphology, the severity of the presentation associated with the homozygous null state coupled with the relatively benign status of heterozygosity has limited their utility.
Wu et al. (9) reported an exceptionally useful line of animals that had a local duplication of the 5' end of Pkd2 that resulted from gene targeting. This fortuitous event resulted in an unstable allele that when combined with a Pkd2 null allele resulted in animals with renal and hepatic disease of variable severity that closely mimics human ADPKD. Despite its unique properties, this model has several features that limit its usefulness to explore the pathobiology of Pkd2: Somatic mutation is random and unregulated, the targeted allele with the local duplication can revert to either a normal or a mutant allele by postmitotic recombination, and one cannot establish with certainty when the somatic events have occurred. The last point is essential if one seeks to determine whether polycystin-2 is necessary for the maintenance of tubular morphology or whether its postdevelopmental loss is an important factor in disease progression because the precise time of gene inactivation cannot be defined. In this report, we describe a new line of mice with a floxed allele of Pkd1 (Pkd1cond/cond) that functions normally in the undeleted state and results in a null allele after cre-mediated deletion of the intervening sequence.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
10 kb that included part of intron 1 through exon 15. Detailed genomic mapping and sequencing confirmed that it was collinear with the corresponding segment of mouse genomic DNA. Two adjacent EcoRI fragments (3 and 7 kb, respectively) were selected for the backbone of the Pkd1cond targeting construct. A neomycin cassette flanked by two FRT sites and a single loxP site at its 3' end (10) (gift of Dr. Gail R. Martin, University of California at San Francisco, San Francisco, CA) was inserted in a BglII site of intron 1 (Figure 1A) 1 kb from the 5' end of the targeting vector. Another loxP site was placed in an XbaI site in intron 4 in the same orientation. The correct orientation and integration of all fragments in the final targeting construct was confirmed by DNA sequence analysis. 129SV-J1 cells were electroporated and subjected to selection of neomycin.
|
gal-null allele has been briefly described elsewhere (11). Briefly, in this line, the bacterial -galactosidase gene was inserted in place of most of mouse Pkd1 exon 2 and all of exon 3 by gene targeting. This allele is a true null with transcriptional termination after the -galactosidase gene but with -galactosidase expression driven by the native Pkd1 promoter. Mice homozygous for the Pkd1gal-null allele are embryonic lethal and have hemorrhages and massive edema with polyhydramnios as described previously for other Pkd1 mutants (5–7). The human -actin FLPe deleter strain (B6;J-strain TgN[ACTFLPe]9205Dym) expresses a thermostable variant of the yeast FLP1 recombinase gene under the direction of the human ACTB promoter and was a gift of Dr. S.M. Dymecki (Harvard Medical School, Boston, MA) (12). The mouse mamillary tumor virus (MMTV)-Cre (B6129BlSw-TgN[MMTV-Cre]4Mam line) express P1 Cre recombinase under the control of the MMTV LTR promoter and was provided by Dr. K.U. Wagner (Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE) (13,14). Meox-cre (B6.129S4-Meox2 tm1[cre]Sor) transgenic mice were obtained from Jackson Laboratory (15). In this line, the Cre recombinase had been "knocked-in" to the Meox2 gene (mesenchyme homeobox 2 gene) locus. Heterozygotes for Cre are phenotypically normal with Cre expression regulated by the native promoter of Meox2. All studies were performed using approved protocols, and animals were housed and cared for in pathogen-free facilities that are accredited by the American Association for the Accreditation of Laboratory Animal Care and meet federal (National Institutes of Health) guidelines for the humane and appropriate care of laboratory animals.
Genotyping
Genomic DNA was prepared from tail specimens using standard procedures. PCR genotyping was performed using the following primers (Figure 2A): F1, AAT AGG GGT GGG GCT TGT GGG TCG; R3: TGG CGA AAG GGG GAT GTG CTG C; R1, TAC TCA CAC CTC CAC CAG TGC; F2, CTA TAG GAC AGG GAT GAC A; R2, CCC TTA CCA ACC CTC TTT A. Pkd1 wild-type (and Pkd1gal-null) and Pkd1cond alleles were identified in 2% 3:1 NuSieve agarose gels as 220- and 250-bp bands, respectively. The Pkd1del2–4 allele was detected as a 0.85-kb band versus a 1.9-kb nondeleted band in 1% agarose gels (Figure 2A; F3, CGA CCA CCA AGC GAA ACA TC; R4, TCG TGT TCC CTT ACC AAC CCT C). The Pkd1cond-neo allele was detected by PCR amplification using the primer set shown in Figure 3A (F4, CCT GCC TTG CTC TAC TTT CC; R5, AGG GCT TTT CTT GCT GGT CT). Details regarding PCR conditions are available upon request. Genomic Southern blots of mouse-tail DNA (5 µg/sample) were prepared using standard techniques and probed with P32-labeled probes generated using gel-purified fragments of cloned DNA as template.
|
|
|
|
Histopathology and Immunohistochemistry
Kidney and liver specimens from adult animals were collected and immediately fixed in 10% buffered formalin at 4°C overnight. Embryos at day 14.5 post coitum were fixed with ice-cold 4% paraformaldehyde in PBS via cardiac perfusion of the mother, placed in 4% paraformaldehyde overnight at 4°C, and then transferred to 70% ethanol before embedding in low-melting paraffin. Sections (5 µm) were deparaffinized with xylene and rehydrated in a graded alcohol series. For immunohistochemistry studies, sections were microwaved for 10 min in citrate buffer solution (pH 6.0) to enhance antigen retrieval, preincubated with monoclonal blocker solution (Zymed Lab), and then incubated overnight at 4°C with 1:500 dilution of 
-LRR, a monoclonal raised against recombinant human LRR domain. The samples were washed twice with PBST (5 min), and signal was detected using substrate-chromagen mixture (Zymed Lab). The LRR mAb was purified using the HiTrap protein G HP Mab Trap Kit (Amersham Biosciences).
Ultrasound Imaging
Kidney ultrasound was performed using either a VisualSonics Vevo 660 imaging system with the RVM (real-time microvisualization) 40-MHz scanhead (VisualSonics, Toronto, Ontario, Canada) or a Sequoia C256 (Acuson, Mountain View, CA) imager with 15-MHz linear array transducer. The liver and kidneys were imaged after sedation. After imaging, the animals were killed and their tissues were harvested for gross and histopathologic analysis.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Functional Inactivation of the Pkd1cond Allele
For testing whether the deletion of exons 2 to 4 would result in a functional null allele (Pkd1del2–4), heterozygous Pkd1cond F1 mice were bred with Meox-Cre transgenic mice to produce Pkd1cond/w male offspring that were also positive for the Meox-cre transgene. Expression of the latter results in deletion of floxed DNA segments in >95% of the carrier’s germline (15). Thus, the majority of its offspring should have either the Pkd1w or the Pkd1del2–4 allele. Given that the homozygous state for null mutations of Pkd1 results in embryonic lethality, we reasoned that Pkd1del2–4/gal-null compound heterozygotes also were unlikely to be viable. We tested this hypothesis by setting up a series of 10 crosses between Pkd1cond/w:Meox2Cre/w male mice and Pkd1gal-null/w:Meox2w/w female mice and evaluated the genotypes of all liveborn animals. As shown in Table 1, no viable animals were identified with the Pkd1del2–4/gal-null genotype, and the observed pattern of genotypes differed significantly from what was predicted on the basis of the parental genotypes (P < 0.001). We did identify viable animals with the Pkd1del2–4 allele, confirming that the cre recombinase was functional and that the targeted allele underwent deletion according to the predicted schema (Figure 4A). We subsequently crossed Pkd1del2–4/w pairs and observed no viable offspring with the Pkd1del2–4/del2–4 genotype out of a total of 80 liveborn mice (Table 2).
|
|
gal-null and Pkd1del2–4/del2–4 genotypes suggested that either allelic combination resulted in embryonic lethality. To confirm this prediction, we performed a series of timed pregnancies and harvested the litters at 14.5 d post coitum. Figure 4B shows several Pkd1del2–4/gal-null embryos from a representative litter. Consistent with our hypothesis, Pkd1del2–4/gal-null embryos exhibited the same phenotype as previously observed for Pkd1gal-null homozygotes with polyhydramnios, gross total body edema, and hemorrhages commonly observed. Figure 4D shows the genotyping of this particular litter with a schema (Figure 4C) demonstrating the different allele sizes for the PCR as well as the corresponding Southern blot (Figure 4E). It should be noted that no other genotype was associated with an abnormal phenotype in utero in these studies. Consistent with these results, day E15.5 Pkd1del2–4/del2–4 embryos had similar findings as well as cystic kidneys and pancreas (Figure 2, A through D). Genomic PCR confirmed that mice homozygous for the Pkd1del2–4 allele had complete loss of the floxed exons, and reverse transcription–PCR analyses showed that mutant transcripts encoded by the allele lacked exons 2 to 4 (Figure 2, E through G). Tissues of Pkd1del2–4/del2–4 embryos also lacked staining for a mAb that recognizes the LRR of human PC-1 (Figure 5). In short, these experiments show conclusively that the Pkd1cond allele leads to a functional null allele when exons 2 to 4 are deleted by cre recombinase.
|
We selected a set of five animals with the Pkd1cond/cond;:MMTVcre genotype and five littermate controls (Pkd1cond/cond) for detailed histopathologic analysis at 10 wk of age. Given that ultrasound had previously been used to assess renal cystic disease in vivo, we performed a pilot study using a 15-MHz Sequoia linear array transducer on the two sets of animals (16). A single 3-mm kidney cyst was seen in only one animal (Pkd1cond/cond:MMTVcre). We then killed the mice and performed post mortem examinations of the kidneys and livers. The cyst that was identified by ultrasound and several smaller cysts were visible on the surface of the organ (Figure 6A). Several small (1 mm) renal cysts were also visible on the surface of kidneys from two additional mice of the same genotype. The two animals that lacked visible cysts on gross examination also did not have any microscopic cysts detected in a histopathologic survey of 100-µm slices. One of the animals with kidney cysts also had one visible liver cyst of 4 mm (Figure 6B). None of the control animals, composed of genotypes Pkdcond/w:MMTVcre, Pkd1w/w:MMTVcre, or Pkd1cond/cond, had any visible or microscopic cysts (Table 3).
|
|
2 mm and of a relatively uniform size. In contrast, none of the kidneys or livers of control animals, composed of genotypes Pkd1cond/w:MMTVcre, Pkd1w/w:MMTVcre, or Pkd1cond/cond, had any cysts (Table 3).
The last of the pairs was also examined by ultrasound imaging with a recently acquired higher resolution apparatus (40 MHz) before tissue harvesting. Ultrasound detected a cyst of 0.5 mm on the right kidney and several hepatic cysts, the largest of which was 3 mm, in the mouse with the Pkd1cond/cond MMTVcre genotype and none in the control (Figure 6, E and G). The initial ultrasound findings were confirmed by the post mortem examination. The liver cysts were immediately visible, and their position and size matched the ultrasound findings. Although the right kidney did not have any visible cysts, the single cyst identified by ultrasound was confirmed by histopathologic analysis of the sectioned tissue (Figure 6, E through H).
One possible explanation for the higher rate of cyst formation associated with the Pkd1cond allele is that the latter is associated with a higher rate of cyst development by mechanisms other than cre-recombinase–mediated deletion. We tested for this possibility by generating compound heterozygous Pkd1cond/gal-null mice and examining tissues of 6-mo-old animals. None of the organs of eight mice, ranging from 10 to 33 wk of age, had signs of cyst development in either kidney or liver. These results are consistent with what we had previously observed in analyses of >100 heterozygous Pkd1gal-null animals. In this latter set, renal and hepatic cysts were rarely observed in animals 6 mo or younger (unpublished observation).
The clear association between the formation of cysts and the Pkd1cond/cond:MMTVcre genotype suggested that cre-mediated somatic deletion of Pkd1 was the likely underlying mechanism. To test this hypothesis, we examined cystic and noncystic tissues for the presence of the Pkd1del2–4 allele. We prepared DNA from sections of cystic liver and from comparable sections of normal liver from control animals and used this as the template for PCR amplification. Two sets of primers were designed for this study (Figure 3A). The first pair flank the floxed segment and produce a 1.9-kb fragment from control specimens and an 0.85-kb fragment after cre-mediated deletion of exons 2 to 4. Given that we were using paraffin-embedded specimens on glass slides as source material for DNA isolation, we were concerned that the quality of DNA might be suboptimal for reliable amplification of the 1.9-kb fragment. Therefore, we used a second primer (F3-R5; Figure 3A) that was positioned nearby and could amplify a fragment of slightly larger size (0.9 kb) than the deleted fragment from undeleted alleles that could be used as a control for PCR. As shown in Figure 3B, primer pair F3-R4 amplified a 0.85-kb deleted product solely from the cystic specimens, whereas adding primer R5 amplified the 0.9-kb fragment from both cystic and control samples. In contrast, primer pair F3-R4 weakly amplified the 1.9-kb undeleted product from control samples. The lack of 1.9-kb product in the cystic sample likely is the result of preferential amplification of the smaller product.
FRT-Flanked Neomycin Gene of Pkd1cond Can Be Removed In Vivo
Most gene-targeting constructs include one or more marker genes that allow selection for the relatively small number of cells that are successfully transfected. In standard "gene knockout" strategies, retention of the selectable marker in the targeted locus after recombination often introduces few problems and may even help ensure successful inactivation of the gene of interest. The risks of untoward effects resulting from a retained marker are far higher when one seeks to develop an allele that can be conditionally inactivated. Even when strategically placed in large introns far from sequences thought essential for proper splicing, the consequences can be unpredictable. Therefore, it is common to flank the selectable marker with additional DNA recombination signals that can be used to delete the marker once it is no longer required. Meyers et al. (10) described a novel way of using both FRT and loxP sites that would allow selective deletion of either the selectable marker or one’s targeted gene segment. An advantage of this approach is that it allows for the possible generation of three different alleles (Figure 7A). In situations in which retention of the selectable marker results in a hypomorphic allele, one can potentially use one targeting event to produce a normal, hypomorphic, and completely null allele. Therefore, we had incorporated into the design of our targeting construct FRT sites that flanked the neomycin gene (Figure 1). We had crossed the original Pkd1cond chimeric male mice to FLPe recombinase female mice to produce Pkd1cond/w:FLPe+ offspring. Southern blot and PCR-based analysis confirmed that the neomycin gene was successfully deleted only in mice that were positive for the FLPe transgene, producing a new Pkd1 allele (Pkd1cond-neo; Figure 7, B and C). However, deletion of the neomycin gene seemed to have no effect on Pkd1 activity in that the phenotypes of homozygotes for the Pkd1cond and Pkd1cond-neo alleles were identical.
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
gal-null, were either embryonic lethal or had perinatal demise. By breeding Pkd1cond/w mice that also were positive for a cre-recombinase to Pkd1gal-null heterozygotes, we could evaluate quickly the functional impact of cre-mediated loss of Pkd1 exons 2 to 4. As expected, embryos with the Pkd1del2–4/-gal-null genotype were present in normal Mendelian ratios and recapitulated the range of phenotypes (edema, polyhydramnios, and hemorrhage) associated with homozygous loss of Pkd1. These results show conclusively that the floxed allele functions as a null allele after cre-mediated deletion. Similar results were obtained using mice from different strains, excluding strain differences as a trivial explanation for our findings. In the studies described, all female mice were BlackSwiss/129SVeV F1 hybrids. The male mice were either C57/Bl6/129SVeV (Pkd1cond) or BlackSwiss/129SVeV (Pkd1gal-null).
An important limitation of the currently available lines of mice with targeted mutations of Pkd1 is that heterozygous animals rarely have cystic disease below 6 mo of age. For example, <10% of our Pkd1gal-null heterozygotes (n > 100) had macroscopic renal cysts at 3 mo of age, and none had liver cysts at <6 mo of age. It is interesting that mice of this genotype universally develop cystic livers if aged 18 mo or more (unpublished observations). These results are in striking contrast with what is observed in humans, in whom renal cysts are a universal and early finding and liver cysts are acquired later and generally are less abundant. These are important differences that if explained might provide insights into the mechanism of disease. Likewise, it is important that one understand the pathophysiology of disease in the mice models if one seeks to use them to test various therapeutic interventions.
We propose several possible explanations for these species differences. One possibility is that the somatic mutation rate of PKD1 in human renal and biliary epithelial cells is significantly higher and lower, respectively, than in the corresponding cell types of mice. An alternative explanation is that species differences in the rate of cyst growth in the two organs account for the observations. In this schema, the rate of somatic mutation may not differ, but instead the rates of proliferation or fluid secretion may significantly affect outcome. Finally, it is possible that the molecular mechanisms that govern cyst formation may differ subtly between organisms. The prevailing view regarding the initiation step of cyst formation is that this process begins when some threshold level of PC1/PC2 receptor/channel activity is breached. This can occur as a result of a decrease in the level of activity of the receptor/channel complex and/or an increase in the threshold level required to establish and maintain normal tubule morphology. In heterozygotes, this may result when acquired mutations disrupt the activity of the previously normal allele. It is also possible, however, that the activity of the PC1/PC2 complex normally decreases with age and that in some cell types of heterozygotes it falls below the minimal level. Either the relative level of activity of the complex or the threshold level required to suppress cyst formation in various organs may differ between the species.
The floxed allele of Pkd1 described in this report can be used to distinguish between these various possibilities. Our studies show that somatic expression of cre recombinase in Pkd1cond/cond mice can result in a null allele and cyst formation. Using this line of animals, one can now examine the consequences of temporally and spatially regulated inactivation of Pkd1. By fixing the time and location of gene inactivation, one can examine what other factors affect the relative rate of cyst growth in the kidney and liver. Similarly, by removing the unpredictability of the timing of somatic mutation, this model offers a uniquely powerful way of testing various interventions on the rate of cyst growth. Our pilot study suggests that high-resolution ultrasound imaging may be a useful, noninvasive method for screening for cysts.
This new line of animals also will be invaluable in the study of numerous other aspects of Pkd1 biology. By controlling the timing of Pkd1 inactivation, one can show in a definitive way that Pkd1 is, in fact, necessary for both formation and maintenance of tubules. Likewise, one can use this model to determine the cause of fetal demise. Using this information, one can selectively inactivate the gene in a manner that bypasses the embryonic lethality and then assess the role of PC1 in the development of various other tissues that are altered in Pkd1 nulls. Finally, one can use this novel model to screen for as-of-yet unidentified postdevelopmental functions of Pkd1 that are not manifest in humans because of the two-hit nature of disease and not observed in mice because of the early lethality associated with its homozygous loss.
|
Acknowledgments |
|---|
We thank members of the Germino laboratory for helpful discussions.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Related Article
J. Am. Soc. Nephrol. 2004 15: 2955-2958.
This article has been cited by other articles:
 |
|
 |
|
  A. Takakura, L. Contrino, A. W. Beck, and J. Zhou Pkd1 Inactivation Induced in Adulthood Produces Focal Cystic Disease J. Am. Soc. Nephrol., December 1, 2008; 19(12): 2351 - 2363. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Shibazaki, Z. Yu, S. Nishio, X. Tian, R. B. Thomson, M. Mitobe, A. Louvi, H. Velazquez, S. Ishibe, L. G. Cantley, et al. Cyst formation and activation of the extracellular regulated kinase pathway after kidney specific inactivation of Pkd1 Hum. Mol. Genet., June 1, 2008; 17(11): 1505 - 1516. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Yu, K. Hackmann, J. Gao, X. He, K. Piontek, M. A. Garcia-Gonzalez, L. F. Menezes, H. Xu, G. G. Germino, J. Zuo, et al. Essential role of cleavage of Polycystin-1 at G protein-coupled receptor proteolytic site for kidney tubular structure PNAS, November 20, 2007; 104(47): 18688 - 18693. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Garcia-Gonzalez, L. F. Menezes, K. B. Piontek, J. Kaimori, D. L. Huso, T. Watnick, L. F. Onuchic, L. M. Guay-Woodford, and G. G. Germino Genetic interaction studies link autosomal dominant and recessive polycystic kidney disease in a common pathway Hum. Mol. Genet., August 15, 2007; 16(16): 1940 - 1950. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Wei, K. Hackmann, H. Xu, G. Germino, and F. Qian Characterization of cis-Autoproteolysis of Polycystin-1, the Product of Human Polycystic Kidney Disease 1 Gene J. Biol. Chem., July 27, 2007; 282(30): 21729 - 21737. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. K. Ahrabi, S. Terryn, G. Valenti, N. Caron, C. Serradeil-Le Gal, D. Raufaste, S. Nielsen, S. Horie, J.-M. Verbavatz, and O. Devuyst PKD1 Haploinsufficiency Causes a Syndrome of Inappropriate Antidiuresis in Mice J. Am. Soc. Nephrol., June 1, 2007; 18(6): 1740 - 1753. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. C. Harris, K. T. Bae, S. Rossetti, V. E. Torres, J. J. Grantham, A. B. Chapman, L. M. Guay-Woodford, B. F. King, L. H. Wetzel, D. A. Baumgarten, et al. Cyst Number but Not the Rate of Cystic Growth Is Associated with the Mutated Gene in Autosomal Dominant Polycystic Kidney Disease J. Am. Soc. Nephrol., November 1, 2006; 17(11): 3013 - 3019. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Shillingford, N. S. Murcia, C. H. Larson, S. H. Low, R. Hedgepeth, N. Brown, C. A. Flask, A. C. Novick, D. A. Goldfarb, A. Kramer-Zucker, et al. From the Cover: The mTOR pathway is regulated by polycystin-1, and its inhibition reverses renal cystogenesis in polycystic kidney disease PNAS, April 4, 2006; 103(14): 5466 - 5471. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Allen, K. B. Piontek, E. Garrett-Mayer, M. Garcia-Gonzalez, K. L. Gorelick, and G. G. Germino Loss of polycystin-1 or polycystin-2 results in dysregulated apolipoprotein expression in murine tissues via alterations in nuclear hormone receptors Hum. Mol. Genet., January 1, 2006; 15(1): 11 - 21. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Li, J. M. Wright, F. Qian, G. G. Germino, and W. B. Guggino Polycystin 2 Interacts with Type I Inositol 1,4,5-Trisphosphate Receptor to Modulate Intracellular Ca2+ Signaling J. Biol. Chem., December 16, 2005; 280(50): 41298 - 41306. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
HOME
CURRENT ISSUE
ARCHIVES
JASN Express
ONLINE SUBMISSION
AUTHOR INFO
EDITORIAL BOARD SUBSCRIBE FEEDBACK ALERTS HELP |
