PKCtheta II, a new isoform of protein kinase C specifically expressed in the seminiferous tubules of mouse testis

Forkhead-box A1 induces cell senescence in endometrial cancer by regulating p16INK4a

We previously identified FOXA1 as a tumor-suppressor in EC cells. In the present study, we sought to delineate the different roles of FOXA1 associated with cell senescence and further investigated the correlation between FOXA1 and p16INK4a in the progression of EC. Using reverse transcription-quantitative PCR (RT-qPCR), we found that FOXA1 expression was significantly downregulated in EC cells compared to that in normal endometrial cells. Functionally, senescence‑associated β-galactosidase staining, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), clonogenic and Transwell assays showed that in addition to acting as a pioneer factor, FOXA1 was significantly upregulated in senescent EC cells. Furthermore, restoration of FOXA1 expression triggered multiple steps of cellular senescence in EC cells and activated p16INK4a expression. All of these findings indicate that FOXA1 promotes cell senescence in EC by interaction with p16INK4a, possibly via the AKT pathway. Notably, a selective PI3K inhibitor raised the possibility that FOXA1‑induced senescence is associated with the AKT pathway in EC cells. Collectively, the present study provides a conceivable molecular mechanism by which cell senescence acts as the barrier to EC, and is regulated by FOXA1-induced p16INK4a expression. This may be a newly identified regulatory mechanism of cell senescence in EC.

Duplicity of protein kinase C-θ: Novel insights into human T-cell biology

We recently reported on a new wrinkle of complexity in how eukaryotic genes are regulated by providing evidence for a hitherto unknown nuclear function of the signaling kinase, Protein Kinase C-theta (PKC-θ). This chromatin-anchored complex positively regulates inducible immune genes and negatively regulates target miRNA genes. These data challenge the traditional view of mammalian signaling kinases and provides new avenues for therapeutic drug design.

The involvement of specific PKC isoenzymes in phorbol ester-mediated regulation of steroidogenic acute regulatory protein expression and steroid synthesis in mouse Leydig cells

Protein kinase C (PKC) is a multigene family of serine/threonine kinases. PKC is involved in regulating adrenal and gonadal steroidogenesis; however, the functional relevance of the different PKC isoenzymes remains obscure. In this study, we demonstrate that MA-10 mouse Leydig tumor cells express several PKC isoforms to varying levels and that the activation of PKC signaling, by phorbol 12-myristate 13-acetate (PMA) elevated the expression and phosphorylation of PKCα, -δ, -ε, and -μ/protein kinase D (PKD). These responses coincided with the expression of the steroidogenic acute regulatory (StAR) protein and progesterone synthesis. Targeted silencing of PKCα, δ, and ε and PKD, using small interfering RNAs, resulted in deceases in basal and PMA-mediated StAR and steroid levels and demonstrated the importance of PKD in steroidogenesis. PKD was capable of controlling PMA and cAMP/PKA-mediated synergism involved in the steroidogenic response. Further studies pointed out that the regulatory events effected by PKD are associated with cAMP response element-binding protein (CREB) and c-Jun/c-Fos-mediated transcription of the StAR gene. Chromatin immunoprecipitation studies revealed that the activation of phosphorylated CREB, c-Jun, and c-Fos by PMA was correlated with in vivo protein-DNA interactions and the recruitment of CREB-binding protein, whereas knockdown of PKD suppressed the association of these factors with the StAR promoter. Ectopic expression of CREB-binding protein enhanced the trans-activation potential of CREB and c-Jun/c-Fos in StAR gene expression. Using EMSA, a -83/-67-bp region of the StAR promoter was shown to bind PKD-transfected MA-10 nuclear extract in a PMA-responsive manner, targeting CREB and c-Jun/c-Fos proteins. These findings provide evidence for the presence of multiple PKC isoforms and demonstrate the molecular events by which selective isozymes, especially PKD, influence PMA/PKC signaling involved in the regulation of the steroidogenic machinery in mouse Leydig cells.

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 5: intercellular junctions and contacts between germs cells and Sertoli cells and their regulatory interactions, testicular cholesterol, and genes/proteins associated with more than one germ cell generation

In the testis, cell adhesion and junctional molecules permit specific interactions and intracellular communication between germ and Sertoli cells and apposed Sertoli cells. Among the many adhesion family of proteins, NCAM, nectin and nectin-like, catenins, and cadherens will be discussed, along with gap junctions between germ and Sertoli cells and the many members of the connexin family. The blood-testis barrier separates the haploid spermatids from blood borne elements. In the barrier, the intercellular junctions consist of many proteins such as occludin, tricellulin, and claudins. Changes in the expression of cell adhesion molecules are also an essential part of the mechanism that allows germ cells to move from the basal compartment of the seminiferous tubule to the adluminal compartment thus crossing the blood-testis barrier and well-defined proteins have been shown to assist in this process. Several structural components show interactions between germ cells to Sertoli cells such as the ectoplasmic specialization which are more closely related to Sertoli cells and tubulobulbar complexes that are processes of elongating spermatids embedded into Sertoli cells. Germ cells also modify several Sertoli functions and this also appears to be the case for residual bodies. Cholesterol plays a significant role during spermatogenesis and is essential for germ cell development. Lastly, we list genes/proteins that are expressed not only in any one specific generation of germ cells but across more than one generation.

17Beta-hydroxysteroid dehydrogenase type 12 in human breast carcinoma: a prognostic factor via potential regulation of fatty acid synthesis

17beta-Hydroxysteroid dehydrogenase type 12 (17beta-HSD12) has been shown to be involved in elongation of very long chain fatty acid (VLCFA) as well as in biosynthesis of estradiol (E2). 17beta-HSD12 expression was also reported in breast carcinomas but its functions have remained unknown. In this study, we examined the correlation between mRNA expression profiles determined by microarray analysis and tissue E2 concentrations obtained from 16 postmenopausal breast carcinoma cases. No significant correlations were detected between 17beta-HSD12 expression and E2 concentration. We then immunolocalized this enzyme in 110 cases of invasive ductal carcinoma. 17beta-HSD12 immunoreactivity in breast carcinoma cells was significantly associated with poor prognosis of the patients. We further examined the biological significance of 17beta-HSD12 using cell-based studies. Small interfering RNA-mediated knockdown of 17beta-HSD12 in SK-BR-3 (estrogen receptor-negative breast carcinoma cell line) resulted in significant growth inhibition, which was recovered by the addition of VLCFAs such as arachidonic acid. The status of 17beta-HSD12 immunoreactivity was also correlated with adverse clinical outcome in cyclooxygenase 2 (COX2)-positive breast cancer patients but not in COX2-negative patients. Therefore, these findings indicated that 17beta-HSD12 was not necessarily related to intratumoral E2 biosynthesis, at least in human breast carcinoma, but was rather correlated with production of VLCFAs such as arachidonic acid, which may subsequently be metabolized to prostaglandins by COX2 and result in tumor progression of the patients.

Alternative splicing in the NF-kappaB signaling pathway

Activation of transcription factor NF-kappaB can affect the expression of several hundred genes, many of which are involved in inflammation and immunity. The proper NF-kappaB transcriptional response is primarily regulated by post-translational modification of NF-kappaB signaling constituents. Herein, we review the accumulating evidence suggesting that alternative splicing of NF-kappaB signaling components is another means of controlling NF-kappaB signaling. Several alternative splicing events in both the tumor necrosis factor and Toll/interleukin-1 NF-kappaB signaling pathways can inhibit the NF-kappaB response, whereas others enhance NF-kappaB signaling. Alternative splicing of mRNAs encoding some NF-kappaB signaling components can be induced by prolonged exposure to an NF-kappaB-activating signal, such as lipopolysaccharide, suggesting a mechanism for negative feedback to dampen excessive NF-kappaB signaling. Moreover, some NF-kappaB alternative splicing events appear to be specific for certain diseases, and could serve as therapeutic targets or biomarkers.

Identification of a novel antiapoptotic human protein kinase C delta isoform, PKCdeltaVIII in NT2 cells

Protein kinase C (PKC) delta plays an important role in cellular proliferation and apoptosis where it is involved in the caspase-3 mediated apoptotic pathway. Cleavage of PKCdeltaI by caspase-3 releases a catalytically active C-terminal fragment that is sufficient to induce apoptosis. In this paper, we identified a novel human PKCdelta isozyme, PKCdeltaVIII (Genbank accession number DQ516383) in human teratocarcinoma (NT2) cells that differentiate into hNT neurons upon retinoic acid (RA) treatment. Expression of PKCdeltaVIII was confirmed by real-time RT-PCR analysis, and we observed that after an initial peak at 24 h following RA treatment, its expression gradually declined with prolonged RA treatment. PKCdeltaVIII is generated via the utilization of an alternative 5' splice site, and this results in an insertion of 31 amino acids in the caspase-3 recognition sequence DMQD. The function of PKCdeltaVIII was examined by subcloning it into an expression vector and raising an antibody specific to PKCdeltaVIII. Using in vivo and in vitro assays, we demonstrated that PKCdeltaVIII is resistant to caspase-3 cleavage. Next, we sought to determine the role of PKCdeltaVIII in apoptosis in NT2 cells. Overexpression of PKCdeltaVIII and knockdown using PKCdeltaVIII siRNA suggest an antiapoptotic function for the PKCdeltaVIII isozyme. We demonstrate that antisense oligonucleotides (ASO) directed toward the 5' splice site I promote the expression of the PKCdeltaVIII isozyme. Our results indicated that ASO mediated PKCdeltaVIII expression rescued NT2 cells from etoposide-induced apoptosis. We conclude that the novel human PKCdeltaVIII splice variant functions as an antiapoptotic protein in NT2 cells.

Differential expression of PKC isoforms in developing zebrafish

Protein kinase C isozymes are a biologically diverse group of enzymes known to be involved in a wide variety of cellular processes. They fall into three families (conventional, novel and atypical) depending upon their mode of activation. Several classes of zebrafish neurons have been shown to express PKCalpha during development, but the expression of other isoforms remains unknown. In this study we performed immunohistochemistry to determine if zebrafish express various isoforms of PKC. We used antibodies to test for the presence of enzymes that are thought to be preferentially expressed in the nervous system (PKCgamma, betaII, delta, epsilon, theta and zeta). Here, we show that PKCgamma, epsilon, theta and zeta are expressed in the zebrafish CNS. Anti-PKCgamma labels Rohon-Beard sensory neurons and Mauthner cells. PKCepsilon and zeta staining is widespread in the CNS, and PKCtheta and betaII are expressed in skeletal muscle, especially at intersegmental boundaries. Immunoblot experiments confirm the specificity of the antibodies in zebrafish and indicate that the fish isoforms of PKCgamma, betaII, epsilon and zeta are similar to the mammalian isoforms. Interestingly, PKCtheta appears to be similar to PKCthetaII, which, to date, has been found exclusively in mouse testis, but not in the mammalian CNS. Overall, our findings indicate that several different PKC isoforms are expressed in zebrafish, and that Rohon-Beard, Mauthner cells and muscle fibers preferentially express some isoforms over others.

New PKCδ family members, PKCδIV, δV, δVI, and δVII are specifically expressed in mouse testis

We isolated and characterized four new PKCdelta isoforms, PKCdeltaIV, deltaV, deltaVI, and deltaVII, specifically expressed in the mouse testis. These isoforms possess neither V1 nor C2-like domains. Moreover, PKCdeltaVI and deltaVII have a different last exon as their V5 domain. The transcription of PKCdeltaIV, deltaV, deltaVI, and deltaVII is initiated from the same site in the upstream region of exon4 of the PKCdelta gene. They are expressed exclusively in the testis in an age-dependent manner. PKCdeltaIV and deltaV are expressed in spermatids with sperm maturation stage-specific manner, and that PKCdeltaVI and deltaVII are expressed in spermatogonia and spermatocytes.

Up-regulation and increased phosphorylation of protein kinase C (PKC) delta, mu and theta in the degenerating rd1 mouse retina

The rd1 mouse serves as a model for inherited photoreceptor degeneration: retinitis pigmentosa. Microarray techniques were employed to compare the transcriptomes of rd1 and congenic wild-type retinas at postnatal day 11, when degenerative processes have started but most photoreceptors are still present. Of the several genes that were differentially expressed, focus was put on those associated with the protein kinase C (PKC) signaling pathway, in particular PKCdelta, mu and theta. Microarray identified these as being up-regulated in the rd1 retina, which was confirmed by QRT-PCR. Western blotting and immunostaining, using antibodies against either total or phosphorylated variants of the PKC isoforms, revealed increased expression and phosphorylation of PKCdelta, mu and theta in the rd1 retina at the protein level as well. Our results suggest that these PKC isoforms are involved in rd1 degeneration.

Expression of the steroid and xenobiotic receptor and its possible target gene, organic anion transporting polypeptide-A, in human breast carcinoma

Steroid and xenobiotic receptor (SXR) or human pregnane X receptor (hPXR) has been shown to play an important role in the regulation of genes related to xenobiotic detoxification, such as cytochrome P450 3A4 and multidrug resistance gene 1. Cytochrome P450 enzymes, conjugation enzymes, and transporters are all considered to be involved in the resistance of breast carcinoma to chemotherapeutic or endocrine agents. However, the expression of SXR/hPXR proteins and that of its target genes and their biological or clinical significance have not been examined in human breast carcinomas. Therefore, we first examined SXR/hPXR expression in 60 breast carcinomas using immunohistochemistry and quantitative reverse transcription-PCR. We then searched for possible SXR/hPXR target genes using microarray analysis of carcinoma cells captured by laser microscissors. SXR/hPXR was detected in carcinoma tissues but not in nonneoplastic and stromal cells of breast tumors. A significant positive correlation was detected between the SXR/hPXR labeling index and both the histologic grade and the lymph node status of the carcinoma cases. Furthermore, in estrogen receptor-positive cases, SXR/hPXR expression was also positively correlated with expression of the cell proliferation marker, Ki-67. Microarray analysis showed that organic anion transporting polypeptide-A (OATP-A) was most closely correlated with SXR/hPXR gene expression, and both OATP-A mRNA and protein were significantly associated with SXR/hPXR in both breast carcinoma tissues and its cell lines. These results suggest that SXR/hPXR and its target gene, such as OATP-A, may play important roles in the biology of human breast cancers.

Genome-wide review of transcriptional complexity in mouse protein kinases and phosphatases

A systematic study of the transcript variants of all protein kinase- and phosphatase-like loci in mouse shows that at least 75% of them generate alternative transcripts, many of which encode different domain structures.

Background

Alternative transcripts of protein kinases and protein phosphatases are known to encode peptides with altered substrate affinities, subcellular localizations, and activities. We undertook a systematic study to catalog the variant transcripts of every protein kinase-like and phosphatase-like locus of mouse .

Results

By reviewing all available transcript evidence, we found that at least 75% of kinase and phosphatase loci in mouse generate alternative splice forms, and that 44% of these loci have well supported alternative 5' exons. In a further analysis of full-length cDNAs, we identified 69% of loci as generating more than one peptide isoform. The 1,469 peptide isoforms generated from these loci correspond to 1,080 unique Interpro domain combinations, many of which lack catalytic or interaction domains. We also report on the existence of likely dominant negative forms for many of the receptor kinases and phosphatases, including some 26 secreted decoys (seven known and 19 novel: Alk, Csf1r, Egfr, Epha1, 3, 5,7 and 10, Ephb1, Flt1, Flt3, Insr, Insrr, Kdr, Met, Ptk7, Ptprc, Ptprd, Ptprg, Ptprl, Ptprn, Ptprn2, Ptpro, Ptprr, Ptprs, and Ptprz1) and 13 transmembrane forms (four known and nine novel: Axl, Bmpr1a, Csf1r, Epha4, 5, 6 and 7, Ntrk2, Ntrk3, Pdgfra, Ptprk, Ptprm, Ptpru). Finally, by mining public gene expression data (MPSS and microarrays), we confirmed tissue-specific expression of ten of the novel isoforms.

Conclusion

These findings suggest that alternative transcripts of protein kinases and phosphatases are produced that encode different domain structures, and that these variants are likely to play important roles in phosphorylation-dependent signaling pathways.

PKCdelta alternatively spliced isoforms modulate cellular apoptosis in retinoic acid-induced differentiation of human NT2 cells and mouse embryonic stem cells

NT2 cells are a human teratocarcinoma cell line that, upon treatment with retinoic acid (RA), begin differentiating into a neuronal phenotype. The transformation of undifferentiated NT2 cells into hNT neurons presents an opportunity to investigate the mechanisms involved in neurogenesis because a key component is cell apoptosis, which is essential for building neural networks. Protein kinase Cdelta (PKCdelta) plays an important role as a mediator of cellular apoptosis in response to various stimuli. PKCdelta (deltaI) is proteolytically cleaved at its hinge region (V3) by caspase 3 and the catalytic fragment is sufficient to induce apoptosis in various cell types. Mouse PKCdeltaII is rendered caspase resistant due to an insertion of 78 bp within the caspase recognition site in its V3 domain. No functional role has been attributed to these alternatively spliced variants of PKCdelta. We sought to find a correlation between the onset of apoptosis, neurogenesis, and the expression of PKCdelta isoforms. Our results indicate that RA regulates the expression of PKCdelta alternative splicing variants in NT2 cells. Further, overexpression of PKCdeltaI promotes apoptosis while PKCdeltaII overexpression shields the cells from apoptosis. This is the first report to attribute physiological function to PKCdeltaI and -deltaII isoforms. Next we demonstrated that mouse embryonic stem cells differentiate in vitro into dopaminergic neurons upon stimulation with RA and ciliary neurotrophic factor. These cells showed a simultaneous increase in tyrosine hydroxylase and PKCdeltaII expression. We suggest that the molecular mechanisms regulating differentiation and apoptosis could be understood by alternative expression of PKCdelta isoforms.

Estrogen-responsive finger protein as a new potential biomarker for breast cancer

PURPOSE

Estrogen-responsive finger protein (Efp) is a member of RING finger-B box-Coiled Coil family and is also a downstream target of estrogen receptor alpha. Previously, Efp was shown to mediate estrogen-induced cell growth, which suggests possible involvement in the development of human breast carcinomas. In this study, we examined expression of Efp in breast carcinoma tissues and correlated these findings with various clinicopathologic variables.

EXPERIMENTAL DESIGN

Thirty frozen specimens of breast carcinomas were used for immunohistochemistry and laser capture microdissection/real-time PCR of Efp. Immunohistochemistry for Efp was also done in 151 breast carcinoma specimens fixed with formalin and embedded in paraffin wax.

RESULTS

Efp immunoreactivity was detected in breast carcinoma cells and was significantly associated with the mRNA level (n = 30). Efp immunoreactivity was positively associated with lymph node status or estrogen receptor alpha status and negatively correlated with histologic grade or 14-3-3sigma immunoreactivity (n = 151). Moreover, Efp immunoreactivity was significantly correlated with poor prognosis of breast cancer patients, and multivariate analyses of disease-free survival and overall survival for 151 breast cancer patients showed that Efp immunoreactivity was the independent marker.

CONCLUSIONS

Our data suggest that Efp immunoreactivity is a significant prognostic factor in breast cancer patients. These findings may account for an oncogenic role of Efp in the tumor progression of breast carcinoma.

Differential gene expression profiles in stage I primary biliary cirrhosis

OBJECTIVES

Primary biliary cirrhosis (PBC) is a progressive disease. However, little is understood about the molecular mechanisms underlying its features.

METHODS

We analyzed gene expression profiles of liver biopsy samples from 16 patients with PBC, seven with autoimmune hepatitis, eight with chronic hepatitis C, and eight normal control livers. In addition to whole liver samples, we selectively analyzed chronic nonsuppurative destructive cholangitis (CNSDC) lesions by laser capture microdissection.

RESULTS

Hierarchical clustering analysis using only early-stage liver disease demonstrated 85 genes were upregulated in stage I PBC specifically. Surprisingly, the expression of these genes was not maintained in advanced-stage PBC, while other gene clusters were upregulated. Expression analysis of CNSDC lesions in stage I PBC showed the presence of active inflammatory changes, characterized by the significant elevation of interferon-gamma and the development and maturation of lymphocytes. Expression of these genes was diminished in lymphoid cells aggregation in stage III PBC, and genes reflecting hepatocyte damage were upregulated with disease progression.

CONCLUSION

Gene expression patterns in stage I PBC are different from others. There are distinct changes in molecular pathology from early- to late-stage PBC, which might be a clue to reveal the etiology and progression of PBC.

Chromatin remodelling and epigenetic features of germ cells

Germ cells have the unique capacity to start a new life upon fertilization. They are generated during a sex-specific differentiation programme called gametogenesis. Maturation of germ cells is characterized by an impressive degree of cellular restructuring and gene regulation that involves remarkable genomic reorganization. These events are finely tuned, but are also susceptible to the introduction of various types of error. Because stable genetic transmission to future generations is essential for life, understanding the control of these processes has far-reaching implications for human health and reproduction.

Steroid and xenobiotic receptor (SXR), cytochrome P450 3A4 and multidrug resistance gene 1 in human adult and fetal tissues

The steroid and xenobiotic receptor (SXR) has been demonstrated to play an important role in the regulation of the cytochrome P450 3A4 gene (CYP3A4) and multidrug resistance gene 1 (MDR1) by both endogenous and xenobiotic substrates. SXR and its rodent ortholog PXR exhibit marked differences in their ability to be activated by xenobiotic inducers. This suggests that results obtained by rodent models may not always accurately predict responses to the same compounds in humans. SXR expression was demonstrated in the human liver and intestine, but its systemic distribution remains unknown. Therefore in this study, we first characterized the expression of SXR and its target genes CYP3A4, and MDR1 in human adult and fetal tissues using quantitative RT-PCR, immunoblotting, and combined laser capture microscopy and RT-PCR analysis. SXR mRNA and protein are expressed in adult and fetal liver, lung, kidney, and intestine. There is a close association between the expression of SXR and its target genes in all of the tissues examined. The amounts of SXR mRNA in the liver and intestine reached maximal levels in young adults (15-38 years old) and then subsequently decreased to less than half of the maximal levels with aging. These findings demonstrated age-related differences in the body's capacity to metabolize steroids and xenobiotic compounds and suggest an important role for SXR and its target genes, CYP3A4 and MDR1 in this process.

Interactions between Prostaglandin E2, Liver Receptor Homologue-1, and Aromatase in Breast Cancer

Local synthesis of estrogens within breast adipose tissue by cytochrome P450 aromatase contributes to the growth of postmenopausal breast cancers. One of the major stimulators of aromatase expression in breast is prostaglandin E2 (PGE2) derived from tumorous epithelium and/or infiltrating macrophages. Recently, the orphan nuclear receptor, liver receptor homologue-1 (LRH-1), has also been shown to regulate aromatase expression in breast adipose tissue. We therefore examined the expression of, and correlations between, aromatase and LRH-1 mRNA in a panel of breast carcinoma tissues and adjacent adipose tissue. LRH-1 mRNA expression was low in normal breast tissue but markedly elevated in both breast carcinoma tissue and adipose tissue surrounding the tumor invasion (thereby paralleling aromatase expression). Laser capture microdissection localized the site of LRH-1 expression to tumor epithelial cells but not to intratumoral stromal cells. A strong correlation between LRH-1 and aromatase mRNA levels was observed in tumor-containing adipose tissue but not in tumor tissue. Ectopic expression of LRH-1 in primary human adipose stromal cells strongly activated endogenous aromatase mRNA expression and enzyme activity. Finally, treatment of adipose stromal cells with PGE2 induced expression of both LRH-1 and aromatase. We suggest that PGE2 derived from breast tumor tissue may increase aromatase expression in the surrounding adipose stroma in part by inducing LRH-1 in these cells. The roles of LRH-1 in breast cancer proliferation merit further study.

Analysis for Localization of Steroid Sulfatase in Human Tissues

Human steroid sulfatase (STS) is an enzyme that hydrolyzes several sulfated steroids, such as estrone sulfate, dehydroepiandrosterone sulfate, and cholesterol sulfate, and results in the production of active substances. STS has been demonstrated in human breast cancer tissues and is considered to be involved in intratumoral estrogen production. It is very important to analyze the cellular distribution of STS with accuracy in human tissues in order to obtain a better understanding of the biological significance of STS. Therefore, this chapter describes several morphological approaches used to study the localization of STS, including immunohistochemistry, mRNA in situ hybridization, and laser capture microdissection/reverse transcription-polymerase chain reaction, in human tissues.

Molecular cloning and characterization of chemokine-like factor super family member 1 (CKLFSF1), a novel human gene with at least 23 alternative splicing isoforms in testis tissue

Chemokine-like factor (CKLF) was isolated from PHA-stimulated U937 cells. It is composed of 152 amino acids and located on chromosome 16q22. Utilizing bioinformatics, based on CKLF cDNA and protein sequences, in combination with experimental validation, we identified a novel gene designated chemokine-like factor super family member 1 (CKLFSF1). CKLFSF1 maps on chromosome 16q22, and the full-length gene comprises of seven exons and six introns. Using RACE-PCR, we identified two potential alternative transcription start sites, 1A and 1B. Northern blot and RT-PCR analysis demonstrated that CKLFSF1 is predominantly expressed in human testis tissue, with only lower levels of expression in many other human tissues. RT-PCR and cDNA sequencing identified 23 alternatively spliced isoforms of CKLFSF1 in the testis tissue, which encode protein variants ranging from 36 to 169 amino acids in length. Immunohistochemistry analysis demonstrated that CKLFSF1 proteins are highly expressed in spermatocyte and in tissue fluid of human testes tissue. In light of these findings, we propose that CKLFSF1 may play an important role in spermatogenesis or testicular development.

Analysis of the clonality of ectopic glands in peritoneal endometriosis using laser microdissection

OBJECTIVE

To investigate the clonality of ectopic gland cells in peritoneal endometriosis.

DESIGN

Prospective study. University hospital.

PATIENT(S)

Seventeen women with surgically diagnosed endometriosis.

INTERVENTION(S)

Samples of peritoneal endometriotic lesions were obtained from patients during laparoscopic surgery.

MAIN OUTCOME MEASURE(S)

Clonality analysis used the laser microdissection technique, a phosphoglycerate kinase (PGK) gene polymorphism assay, and an androgen receptor (AR) gene polymorphism assay after digestion of the DNA with methylation-sensitive endonuclease.

RESULT(S)

Each ectopic gland of the peritoneal endometriotic lesion showed a monoclonal pattern in both the PGK gene and AR gene assays, but the methylation pattern of the PGK gene and/or AR gene was divergent among adjacent glands in the lesion. These data indicate that the peritoneal endometriotic lesions are multicellular in origin, although individual glands of the lesion are derived from single precursor cells.

CONCLUSION(S)

The colored peritoneal endometriotic lesion in the present study was multicellular in origin. Peritoneal endometriotic lesions may thus be initiated by transplantation of a cluster of eutopic endometrial tissues into the pelvis.

Protein kinase M zeta synthesis from a brain mRNA encoding an independent protein kinase C zeta catalytic domain. Implications for the molecular mechanism of memory

Protein kinase M zeta (PKM zeta) is a newly described form of PKC that is necessary and sufficient for the maintenance of hippocampal long term potentiation (LTP) and the persistence of memory in Drosophila. PKM zeta is the independent catalytic domain of the atypical PKC zeta isoform and produces long term effects at synapses because it is persistently active, lacking autoinhibition from the regulatory domain of PKC zeta. PKM has been thought of as a proteolytic fragment of PKC. Here we report that brain PKM zeta is a new PKC isoform, synthesized from a PKM zeta mRNA encoding a PKC zeta catalytic domain without a regulatory domain. Multiple zeta-specific antisera show that PKM zeta is expressed in rat forebrain as the major form of zeta in the near absence of full-length PKC zeta. A PKC zeta knockout mouse, in which the regulatory domain was disrupted and catalytic domain spared, still expresses brain PKM zeta, indicating that this form of PKM is not a PKC zeta proteolytic fragment. Furthermore, the distribution of brain PKM zeta does not correlate with PKC zeta mRNA but instead with an alternate zeta RNA transcript thought incapable of producing protein. In vitro translation of this RNA, however, generates PKM zeta of the same molecular weight as that in brain. Metabolic labeling of hippocampal slices shows increased de novo synthesis of PKM zeta in LTP. Because PKM zeta is a kinase synthesized in an autonomously active form and is necessary and sufficient for maintaining LTP, it serves as an example of a link coupling gene expression directly to synaptic plasticity.

Steroid sulfatase and estrogen sulfotransferase in the atherosclerotic human aorta

Various epidemiological studies have demonstrated a relatively low incidence of cardiovascular events in premenopausal women and its marked increment after menopause. In addition, estrogens have been postulated to exert direct anti-atherogenic effects via binding to estrogen receptors in vascular smooth muscle cells (VSMCs). However, not all postmenopausal women develop atherosclerosis despite decreased levels of serum estrogen. Therefore, we believe it is important to examine the status of estrogen metabolism in situ in the human cardiovascular system. Estrone sulfate (E1S) is a major circulating plasma estrogen that is converted into the biologically active estrogen, estrone (E1) by steroid sulfatase (STS). E1 is also sulfated and reverted into E1S by estrogen sulfotransferase (EST). These two enzymes have recently been shown to play important roles in the in situ estrogen actions of estrogen-dependent human tissues and various sex steroid-dependent tumors. STS and EST, however, have not been studied in detail in the human vascular system associated with atherosclerotic changes. In the present study, we evaluated the relative abundance of STS- and EST-immunoreactive protein and mRNA expression in human aorta using immunohistochemistry and reverse transcription followed by quantitative polymerase chain reaction in addition to enzyme activity. STS expression levels were found to be significantly higher in the VSMCs obtained from female aortas with mild atherosclerotic changes than in those with severe atherosclerotic changes and in male aortas regardless of atherosclerotic changes. EST expression levels in the VSMCs of these aortas, however, were significantly higher in female aortas with severe atherosclerotic changes and in male aortas than in female aortas with mild atherosclerotic changes. We believe it is important to examine factors regulating the expression and activity of these estrogen-metabolizing enzymes in the human aorta. Various cytokines have been proposed to function as regulators of these enzymes in other tissues. In the present study, we studied the effects of interleukin (IL)-1beta, known to be produced in human atherosclerotic lesions, on the expression of these enzymes using cultured human VSMCs originally obtained from a female patient. IL-1beta markedly inhibited the expression of STS mRNA and enzyme activity, but stimulated the expression of EST mRNA and enzyme activity. In addition, IL-1beta also reduced E2 production from E1S and E1 in VSMCs. Results from the present study seem to suggest that the expression levels of both STS and EST mRNA and activity may be significantly associated with the degree of atherosclerotic changes in the female aorta, which may be related to cytokines produced in situ, such as IL-1beta, in human atherosclerotic lesions.

Protein kinase C theta affects Ca2+ mobilization and NFAT cell activation in primary mouse T cells

Protein kinase C (PKC)theta is an established component of the immunological synapse and has been implicated in the control of AP-1 and NF-kappaB. To study the physiological function of PKCtheta, we used gene targeting to generate a PKCtheta null allele in mice. Consistently, interleukin 2 production and T cell proliferative responses were strongly reduced in PKCtheta-deficient T cells. Surprisingly, however, we demonstrate that after CD3/CD28 engagement, deficiency of PKCtheta primarily abrogates NFAT transactivation. In contrast, NF-kappaB activation was only partially reduced. This NFAT transactivation defect appears to be secondary to reduced inositol 1,4,5-trisphosphate generation and intracellular Ca2+ mobilization. Our finding suggests that PKCtheta plays a critical and nonredundant role in T cell receptor-induced NFAT activation.

Systemic distribution of steroid sulfatase and estrogen sulfotransferase in human adult and fetal tissues

Estrogens play a key role in various target tissues. Enzymes involved in the biosynthesis and metabolism of these sex steroids also regulate estrogenic actions in these tissues. Estrone sulfate (E1S) is a major circulating plasma estrogen that is converted into the biologically active estrogen, estrone (E1), by steroid sulfatase (STS). E1 is also sulfated and reverted into E1S by estrogen sulfotransferase (EST). These two enzymes have recently been shown to play important roles in the in situ estrogen actions of various sex steroid-dependent human tumors. However, the distribution of STS and EST in normal adult and fetal human tissues remains largely unknown. Therefore, in this study, in addition to examining the tissue distribution of both STS and EST mRNA in human adult and fetal tissues using RT followed by quantitative PCR, we studied the activity of these enzymes using (3)H-labeled E1/E1S as substrates in the homogenates of various human adult tissues. We also examined the localization of STS and EST protein in human adult and fetal tissues using immunohistochemistry, and that of EST mRNA in the adult kidney using laser dissection microscopy and PCR. STS mRNA, enzyme activity, and immunoreactivity were either absent or detected at very low levels in all adult and fetal tissues examined in this study. EST mRNA expression, however, was detected in all of the tissues examined, except for adult spleen and pancreas. EST enzyme activities were consistent with those of mRNA expression in the great majority of the tissues examined. Marked EST immunoreactivity was detected in hepatocytes, adrenal gland (adult, zona fasciculate to the reticularis; fetus, fetal zone), and epithelial cells of the gastrointestinal tract, smooth muscle cells of the tunica media in aorta, Leydig cells of the testis, and syncytiotrophoblast of the placenta. Patterns of EST immunolocalization were similar between adult and fetal human tissues, but EST immunoreactivity was detected in the urinary tubules of adult kidney, whereas in the fetal kidney, it was localized in the interstitial cells surrounding the urinary tubules. In the adult kidney, the presence of EST mRNA was also confirmed in the cells of urinary tubules using laser dissection microscopy and RT-PCR. Although the number of human tissues available for examination in this study was limited, our results suggest that between the enzymes involved in estrogen activation or inactivation, EST and not STS is the more widely expressed enzyme in various peripheral tissues in humans. We speculate that EST may play an important role in protecting peripheral tissues from possible excessive estrogenic effects.

Protein kinase C-theta;: signaling from the center of the T-cell synapse

The hypothesis that protein kinase C (PKC)-theta; plays an important role in T-lymphocyte activation, as indicated by numerous studies in cell lines, was recently confirmed in mice deficient in the expression of this enzyme. In response to TCR stimulation, peripheral T cells lacking PKC-theta; failed to activate NF-kappaB and AP-1, and to express IL-2. This revealed a critical function for this PKC family member in linking membrane-proximal activation cascades to transcriptional responses governing T-cell activation. Although the molecular interactions in which PKC-theta; engages have not been fully delineated, insights from a variety of recent studies have permitted new models to be formulated regarding the mechanisms through which it achieves its unique effector functions.

Molecular genetics and structural genomics of the human protein kinase C gene module

BACKGROUND

Protein kinase C (PKC) has become a major focus among cell biologists interested in second-messenger signal transduction and much has been learned about differences in the cellular localization and function of its different isotypes. In this study we systematically address the genomic locations and gene structures of the human PKC gene module.

RESULTS

We first carried out fine chromosomal mapping of all nine PKC genes by fluorescence in situ hybridization (FISH), using cosmid and BAC probes. The PKC genes are found to be dispersed throughout the genome, and in some positions distinct from those previously reported: PKCalpha is at 17q24, PKCbeta at 16p12, PKCgamma at 19q13.4, PKCdelta at 3p21.2, PKCepsilon at 2p21, PKCzeta at 1p36.3, PKCeta at 14q22-23, PKCtheta; at 10p15 and PKCiota at 3q26. For PKCiota, an additional FISH signal mapped on Xq21.3 revealed a pseudogene (derived by retrotransposition). PKCgamma, zeta, and theta; are found to map to the most distal positions on the chromosomes, potentially implicating telomere position effects in their expression. Using the complete human genome draft sequence and bioinformatics tools, we then carried out a systematic analysis of PKC gene structure, including determination of the occurrence of single-nucleotide polymorphisms corresponding to the PKC loci.

CONCLUSION

This resource of genomic information now facilitates investigation of the PKC gene module in structural chromosomal abnormalities and human disease locus mapping studies.