Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CLN3”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed2001

Tripeptidyl-peptidase I in neuronal ceroid lipofuscinoses and other lysosomal storage disorders.

The classic late infantile form of neuronal ceroid lipofuscinosis (CLN2, cLINCL) is associated with mutations in the gene encoding tripeptidyl-peptidase I (TPP-I), a lysosomal aminopeptidase that cleaves off tripeptides from the free N-termini of oligopeptides. To date over 30 different mutations and 14 polymorphisms associated with CLN2 disease process have been identified. In the present study, we analysed the molecular basis of 15 different mutations of TPP-I by using immunocytochemistry, immunofluorescence, Western blotting, enzymatic assay and subcellular fractionation. In addition, we studied the expression of TPP-I in other lysosomal storage disorders such as CLN1, CLN3, muccopolysaccharidoses and GM1 and GM2 gangliosidoses. Our study shows that TPP-I is absent or appears in very small amounts not only in cLINCL subjects with mutations producing severely truncated protein, but also in individuals with missense point mutations, which correlates with loss of TPP-I activity. Of interest, small amounts of TPP-I were detected in lysosomal fraction from fibroblasts from cLINCL subject with protracted form. This observation suggests that the presence of small amounts of TPP-I in lysosomes is able to delay significantly CLN2 disease process. We also show that TPP-I immunoreactivity is increased in the brain tissue of CLN1 and CLN3 subjects, stronger in glial cells and macrophages than neurons. Less prominent increase of TPP-I staining was found in muccopolysaccharidoses and GM1 and GM2 gangliosidoses. These data suggest that TPP-I participates in lysosomal turnover of proteins in pathological conditions associated with cell/tissue injury.

Aminopeptidases↗
PubMed2001

CLN-3 protein is expressed in the pancreatic somatostatin-secreting delta cells.

Juvenile neuronal ceroid lipofuscinosis (JNCL) is a severe autosomal recessive neurodegenerative disorder resulting from mutations in the CLN3 gene. The gene product is a 438-amino acid hydrophobic peptide of unknown function containing five transmembrane domains. In order to study the tissue distribution of the peptide, polyclonal antibodies were raised in rabbits to three epitopes and were affinity purified before use. All three antibodies were used together for immunocytochemical staining of human pancreas. This staining showed localization in pancreatic islet cells. Double labelling of the tissue indicated that cells staining for the CLN3 protein were also positive for somatostatin.

Animals↗
PubMed1997

Genetic linkage analysis of a variant of juvenile onset neuronal ceroid lipofuscinosis with granular osmiophilic deposits.

A number of variant forms of the neuronal ceroid lipofuscinoses (NCL) have been described and remain unmapped. The genes for infantile (CLN1), juvenile (CLN3) and Finnish-variant late-infantile (CLN5) have previously been mapped to chromosome regions 1p32, 16p12 and 13q21.1-32 respectively. The locus for a variant form of juvenile onset NCL characterised by cytosomal granular osmiophilic deposits (GROD) has been excluded from the CLN3 region of chromosome 16. This study describes the outcome of genetic linkage analysis in four families with this variant at the loci for the CLN1 and CLN5 genes. Using highly informative microsatellite markers tightly linked to the CLN5 locus we have excluded the JNCL variant with GROD from this region. Marker typing across the CLN1 region suggests that JNCL with GROD may be an allelic variant of infantile NCL.

Adolescent↗
PubMed1997

Upregulation of Bcl-2 and elevation of ceramide in Batten disease.

The late infantile and juvenile variants of Batten disease are genetically distinct neurodegenerative disorders. Hallmarks of Batten disease include cognitive and motor decline, seizures and blindness due to retinitis pigmentosa. Recently, the CLN3 gene responsible for the juvenile variant has been cloned. Also, apoptosis was proven to be the mechanism by which neurons and photoreceptors die. This paper provides mechanistic support for the occurrence of apoptosis in this disease: There was marked upregulation of Bcl-2 in brain from the late infantile and juvenile types at the protein and RNA levels both by immunocytochemistry and by Northern blot analysis; there were also a 42% to 197% increase in brain ceramide determinations in brains from three patients with the juvenile type and three patients with the late infantile type. Double immunolabeling of brain sections for apoptosis and Bcl-2 supported a protective role for Bcl-2 in the juvenile form of Batten disease. These results raise the possibility that the intact CLN3 gene is normally antiapoptotic, and that it could be an upstream regulator of ceramide.

Adolescent↗
PubMed1991

FUS3 represses CLN1 and CLN2 and in concert with KSS1 promotes signal transduction.

FUS3 is functionally redundant with KSS1, a homologous yeast protein kinase, for a step(s) in signal transduction between the beta subunit of the guanine nucleotide binding protein (G protein), STE4, and the mating type-specific transcriptional activator, STE12. Either FUS3 or KSS1 can execute this function; when neither gene encoding these protein kinases is present, signal transduction is blocked, causing sterility. This functional redundancy is strain dependent; some standard laboratory strains (S288C) are kss1-. FUS3 has additional functions required for cell cycle arrest and vegetative growth that do not overlap with KSS1 functions. FUS3 mediates cell cycle arrest during mating through transcriptional repression of two G1 cyclins (CLN1 and CLN2) and through posttranscriptional inhibition of a third G1 cyclin (CLN3). FUS3 is also required for vegetative growth in haploid strains dependent upon CLN3 for cell cycle progression but is not required in strains dependent upon either CLN1 or CLN2, suggesting a functional divergence among the three G1 cyclins. The diverse roles for FUS3 suggest that the FUS3 protein kinase has multiple substrates, some of which may be shared with KSS1.

Cell Cycle↗
PubMed1996

Transcriptional remodeling and G1 arrest in dioxygen stress in Saccharomyces cerevisiae.

Saccharomyces cerevisiae, which lack a functional SOD1 gene, encoding the cytosolic Cu,Zn-superoxide dismutase (SOD1), exhibit a variety of metabolic defects in aerobic but not in anaerobic growth. We test here the hypothesis that some of these defects may be due to specific transcriptional changes programmed for cell survival under dioxygen stress. Analysis of the budding pattern and generation time showed that the slower proliferation of an sod1Delta mutant strain under air was due to an increase from 42 to 89 min spent in the G1 phase of the cell cycle. This delay in G1 was not due to an overall decline in biosynthetic activity since total protein and mRNA synthesis was not reduced even under 100% O2. However, rRNA synthesis was strongly decreased, e.g. by 80% in the mutant under 100% O2 (in comparison to N2). Under these conditions, the mutant permanently arrested in G1; this arrest was due to an inhibition of the Start function that prepares yeast for S phase. This Start arrest was due to an inhibition of transcription of the autoregulated G1 cyclins, CLN1 and CLN2; the transcription of the constitutive G1 cyclin, CLN3, was unaffected by the stress. Expression of a hyperstable Cln3 prevented the G1 arrest, indicating that it was due solely to the inhibition of cell cycle-dependent cyclin expression. This remodeling of transcription in oxidative stress was seen also in the inhibition of glucose derepression of SUC2 expression. In contrast, the signaling and activation of mating pheromone (FUS1) and copper-responsive (CUP1) promoter activity were not affected by dioxygen stress, while genes encoding other anti-oxidant enzymes (SOD2, CTT1 and CTA1) were strongly induced. The UBI loci, encoding ubiquitin, were particularly good examples of this pattern of negative and positive transcriptional response to the stress. UBI1-UBI3 expression was repressed in the mutant under 100% O2, while expression of UBI4 was strongly induced. The data demonstrate that extensive remodeling of transcription occurs in yeast under a strong dioxygen stress. This remodeling results in a pattern of expression of gene products needed for defense and repair, and suppression of activities associated with normal proliferative growth.

Cyclins↗
PubMed1999

Recovery of the yeast cell cycle from heat shock-induced G(1) arrest involves a positive regulation of G(1) cyclin expression by the S phase cyclin Clb5.

In the yeast Saccharomyces cerevisiae, heat shock stress induces a variety of cellular responses including a transient cell cycle arrest before G(1)/S transition. Previous studies have suggested that this G(1) delay is probably attributable to a reduced level of the G(1) cyclin gene (CLN1 and CLN2) transcripts. Here we report our finding that the G(1) cyclin Cln3 and the S cyclin Clb5 are the key factors required for recovery from heat shock-induced G(1) arrest. Heat shock treatment of G(1) cells lacking either CLN3 or CLB5/CLB6 functions leads to prolonged cell cycle arrest before the initiation of DNA synthesis, concomitant with a severe deficiency in bud formation. The inability of the clb5 clb6 mutant to resume normal budding after heat shock treatment is unanticipated, since the S phase cyclins are generally thought to be required mainly for initiation of DNA synthesis and have no significant roles in bud formation in the presence of functional G(1) cyclins. Further studies reveal that the accumulation of G(1) cyclin transcripts is markedly delayed in the clb5 clb6 mutant following heat shock treatment, indicating that the CLN gene expression may require Clb5/Clb6 to attain a threshold level for driving the cell cycle through G(1)/S transition. Consistent with this assumption, overproduction of Clb5 greatly enhances the transcription of at least two G(1) cyclin genes (CLN1 and CLN2) in heat-shocked G(1) cells. These results suggest that Clb5 may positively regulate the expression of G(1) cyclins during cellular recovery from heat shock-induced G(1) arrest. Additional evidence is presented to support a role for Clb5 in maintaining the synchrony between budding and DNA synthesis during normal cell division as well.

Cyclin B↗
PubMed2006

Autophagy is disrupted in a knock-in mouse model of juvenile neuronal ceroid lipofuscinosis.

Juvenile neuronal ceroid lipofuscinosis is caused by mutation of a novel, endosomal/lysosomal membrane protein encoded by CLN3. The observation that the mitochondrial ATPase subunit c protein accumulates in this disease suggests that autophagy, a pathway that regulates mitochondrial turnover, may be disrupted. To test this hypothesis, we examined the autophagic pathway in Cln3(Deltaex7/8) knock-in mice and CbCln3(Deltaex7/8) cerebellar cells, accurate genetic models of juvenile neuronal ceroid lipofuscinosis. In homozygous knock-in mice, we found that the autophagy marker LC3-II was increased, and mammalian target of rapamycin was down-regulated. Moreover, isolated autophagic vacuoles and lysosomes from homozygous knock-in mice were less mature in their ultrastructural morphology than the wild-type organelles, and subunit c accumulated in autophagic vacuoles. Intriguingly, we also observed subunit c accumulation in autophagic vacuoles in normal aging mice. Upon further investigation of the autophagic pathway in homozygous knock-in cerebellar cells, we found that LC3-positive vesicles were altered and overlap of endocytic and lysosomal dyes was reduced when autophagy was stimulated, compared with wildtype cells. Surprisingly, however, stimulation of autophagy did not significantly impact cell survival, but inhibition of autophagy led to cell death. Together these observations suggest that autophagy is disrupted in juvenile neuronal ceroid lipofuscinosis, likely at the level of autophagic vacuolar maturation, and that activation of autophagy may be a prosurvival feedback response in the disease process.

Animals↗
PubMed2000

Molecular diagnosis of and carrier screening for the neuronal ceroid lipofuscinoses.

The neuronal ceroid lipofuscinoses (NCLs) are a large group of autosomal recessive lysosomal storage disorders with both enzymatic deficiency and structural protein dysfunction. Three typical forms, the infantile (INCL), late-infantile (LINCL), and juvenile (JNCL), are among the most common childhood-onset neurodegenerative disorders. They result from mutations on genes CLN1, CLN2, and CLN3, respectively. We determined that the mutations 223A --> G and 451C --> T in CLN1, T523-1G --> C, and 636 C --> T in CLN2, and deletion of a 1.02-kb genomic fragment in CLN3 are the five common mutations for NCL. To offer clinical genetic testing for the NCLs, we have developed simple and quick PCR-based molecular tests for detecting INCL-, LINCL-, and JNCL-affected individuals from 180 NCL families (27 INCL, 76 LINCL, and 77 JNCL). The sensitivity of testing to detect NCL patients among clinically suspected individuals was determined to be 78% (21/27) for INCL, 66% (54/76) for LINCL, and 75% (58/77) for JNCL. When molecular screening for carriers was conducted among the normal siblings or parents of the probands, we identified two carriers out of three individuals tested for INCL, 20/56 (35.7%) carriers for LINCL, and 48/106 (45.3%) carriers for JNCL families. In addition, 5% (9/180) of NCL patients revealed genetic heterogeneity and were reclassified. Seven patients previously diagnosed as having JNCL were now found to carry mutations of CLN2 (5/7) or CLN1 (2/7) and 2 with late-infantile onsets were identified as carrying mutations of CLN1. Our data demonstrate the importance of DNA testing to detect accurately both affected individuals and carriers in NCL families.

Adolescent↗
PubMed1997

Human CPR (cell cycle progression restoration) genes impart a Far- phenotype on yeast cells.

Regulated cell cycle progression depends on the proper integration of growth control pathways with the basic cell cycle machinery. While many of the central molecules such as cyclins, CDKs, and CKIs are known, and many of the kinases and phosphatases that modify the CDKs have been identified, little is known about the additional layers of regulation that impinge upon these molecules. To identify new regulators of cell proliferation, we have selected for human and yeast cDNAs that when overexpressed were capable of specifically overcoming G1 arrest signals from the cell cycle branch of the mating pheromone pathway, while still maintaining the integrity of the transcriptional induction branch. We have identified 13 human CPR (cell cycle progression restoration) genes and 11 yeast OPY (overproduction-induced pheromone-resistant yeast) genes that specifically block the G1 arrest by mating pheromone. The CPR genes represent a variety of biochemical functions including a new cyclin, a tumor suppressor binding protein, chaperones, transcription factors, translation factors, RNA-binding proteins, as well as novel proteins. Several CPR genes require individual CLNs to promote pheromone resistance and those that require CLN3 increase the basal levels of Cln3 protein. Moreover, several of the yeast OPY genes have overlapping functions with the human CPR genes, indicating a possible conservation of roles.

Amino Acid Sequence↗
PubMed1999

POG1, a novel yeast gene, promotes recovery from pheromone arrest via the G1 cyclin CLN2.

In the absence of a successful mating, pheromone-arrested Saccharomyces cerevisiae cells reenter the mitotic cycle through a recovery process that involves downregulation of the mating mitogen-activated protein kinase (MAPK) cascade. We have isolated a novel gene, POG1, whose promotion of recovery parallels that of the MAPK phosphatase Msg5. POG1 confers alpha-factor resistance when overexpressed and enhances alpha-factor sensitivity when deleted in the background of an msg5 mutant. Overexpression of POG1 inhibits alpha-factor-induced G1 arrest and transcriptional repression of the CLN1 and CLN2 genes. The block in transcriptional repression occurs at SCB/MCB promoter elements by a mechanism that requires Bck1 but not Cln3. Genetic tests strongly argue that POG1 promotes recovery through upregulation of the CLN2 gene and that the resulting Cln2 protein promotes recovery primarily through an effect on Ste20, an activator of the mating MAPK cascade. A pog1 cln3 double mutant displays synthetic mutant phenotypes shared by cell-wall integrity and actin cytoskeleton mutants, with no synthetic defect in the expression of CLN1 or CLN2. These and other results suggest that POG1 may regulate additional genes during vegetative growth and recovery.

Cyclins↗
PubMed1997

Loci for classical and a variant late infantile neuronal ceroid lipofuscinosis map to chromosomes 11p15 and 15q21-23.

The childhood neuronal ceroid lipofuscinoses (NCLs) are a group of autosomal recessive neurodegenerative disorders characterised by progressive visual failure, neurodegeneration, epilepsy and the accumulation of an autofluorescent lipopigment in neurones and other cells. Three main subtypes have been identified according to age of onset, clinical features and ultrastructural morphology. These are infantile NCL (INCL; CLN1), classical late infantile NCL (LINCL; CLN2) and juvenile NCL (JNCL; CLN3). Several atypical forms of late infantile NCL (LINCL) have also been described including a Finnish variant LINCL (CLN5). The CLN2 gene has been excluded from the CLN1, CLN3 and CLN5 loci. A genome search was initiated using a homozygosity mapping strategy in five classical LINCL and two variant LINCL consanguineous families. A common region of homozygosity was identified on chromosome 11p15 in two of the classical families. Analysis of a further 33 classical LINCL families supported linkage in this region (Zmax = 3.07 at theta = 0.06 at D11S1338). A common region of homozygosity was also observed on chromosome 15q21-23 in the two variant LINCL families. Extension of the analysis to include a further seven families of identical ultrastructural phenotype established linkage to this region (Zmax = 6.00 at theta = 0.00 at D15S1020).

Child, Preschool↗
PubMed1999

The Batten disease gene product (CLN3p) is a Golgi integral membrane protein.

Batten disease (juvenile neuronal ceroid lipofuscinosis) is a recessive neurodegenerative disorder of childhood. The gene, CLN3, was recently identified and found to encode a novel 438 amino acid protein of unknown function. In order to gain insight into the function of the Batten disease protein (CLN3p), we investigated its subcellular localization. Protein constructs incorporating CLN3p fused to the green fluorescence protein or an eight amino acid peptide tag were transiently expressed in fibroblasts, HeLa and COS-7 cells. A juxtanuclear, asymmetric localization pattern was observed that correlated with the Golgi apparatus in all three cell types. However, a proportion of transiently transfected cells exhibited a punctate vesicular distribution throughout the cytoplasm in addition to or without the Golgi localization. In order to account for localization patterns arising from intracellular protein transport disruption due to exaggerated overexpression in transiently transfected cells, we isolated a stably transfected cell line expressing only one copy of the CLN3 -GFP DNA construct. Fluorescence and biochemical analyses using this cell line demonstrated that CLN3p is an integral membrane protein that localizes primarily in the Golgi apparatus. The functional implications of this finding are discussed.

Animals↗
PubMedDate not supplied

Heterogeneity of late-infantile neuronal ceroid lipofuscinosis.

PURPOSE: Late-infantile neuronal ceroid lipofuscinosis (LINCL), an autosomal recessively inherited lysosomal storage disorder characterized by autofluorescent inclusions and rapid progression of neurodegeneration, is due to CLN2 gene mutations. However, CLN2 mutation analysis has failed to identify some clinically diagnosed "late-infantile" NCL cases. This study was conducted to further characterize genetic heterogeneity in families affected by LINCL. METHODS: DNA mutations in the CLN1, CLN2, and CLN3 genes that underlie INCL (infantile NCL), LINCL, and JNCL (juvenile NCL), respectively, were studied with molecular analyses. RESULTS: A total of 252 families affected by childhood NCL were studied. Of 109 families clinically diagnosed as having LINCL, 3 were determined to have either INCL or JNCL by identification of mutation(s) in CLN1 or CLN3. Six families diagnosed initially as having JNCL were found to have LINCL based on the finding of mutations in the CLN2 gene. In addition, several novel mutations were identified. CONCLUSIONS: Clinical and genetic heterogeneity of LINCL was demonstrated in nine LINCL families studied.

Aminopeptidases↗
PubMed1994

Collaboration of G1 cyclins in the functional inactivation of the retinoblastoma protein.

The retinoblastoma gene product (pRB) constrains cell proliferation by preventing cell-cycle progression from the G1 to S phase. Its growth-inhibitory effects appear to be reversed by hyperphosphorylation occurring during G1. This process is thought to involve G1 cyclins and cyclin-dependent kinases (cdks). Here we report that the cell cycle-dependent phosphorylation of mammalian pRB is faithfully reproduced when it is expressed in Saccharomyces cerevisiae. As is the case in mammalian cells, this phosphorylation requires an intact oncoprotein-binding domain and is inhibited by a negative growth factor, in this case a mating pheromone. Expression of pRB in cln (-) mutants indicates that specific combinations of endogenous G1 cyclins, Cln3 and either Cln1 or Cln2 are required for pRB hyperphosphorylation in yeast. Moreover, expression of mammalian G1 cyclins in cln (-) yeast cells indicates that the functions of Cln2 and Cln3 in pRB hyperphosphorylation can be complemented by human cyclin E and cyclin D1, respectively. These observations suggest a functional heterogeneity among G1 cyclin-cdk complexes and indicate a need for the involvement of multiple G1 cyclins in promoting pRB hyperphosphorylation and resulting cell-cycle progression.

CDC28 Protein Kinase, S cerevisiae↗
PubMed2005

Cyclin Cln3p links G1 progression to hyphal and pseudohyphal development in Candida albicans.

G1 cyclins coordinate environmental conditions with growth and differentiation in many organisms. In the pathogen Candida albicans, differentiation of hyphae is induced by environmental cues but in a cell cycle-independent manner. Intriguingly, repressing the G1 cyclin Cln3p under yeast growth conditions caused yeast cells to arrest in G1, increase in size, and then develop into hyphae and pseudohyphae, which subsequently resumed the cell cycle. Differentiation was dependent on Efg1p, Cph1p, and Ras1p, but absence of Ras1p was also synthetically lethal with repression of CLN3. In contrast, repressing CLN3 in environment-induced hyphae did not inhibit growth or the cell cycle, suggesting that yeast and hyphal cell cycles may be regulated differently. Therefore, absence of a G1 cyclin can activate developmental pathways in C. albicans and uncouple differentiation from the normal environmental controls. The data suggest that the G1 phase of the cell cycle may therefore play a critical role in regulating hyphal and pseudohyphal development in C. albicans.

Blotting, Northern↗
PubMed1993

Connections between the Ras-cyclic AMP pathway and G1 cyclin expression in the budding yeast Saccharomyces cerevisiae.

We have identified two processes in the G1 phase of the Saccharomyces cerevisiae cell cycle that are required before nutritionally arrested cells are able to return to proliferative growth. The first process requires protein synthesis and is associated with increased expression of the G1 cyclin gene CLN3. This process requires nutrients but is independent of Ras and cyclic AMP (cAMP). The second process requires cAMP. This second process is rapid, is independent of protein synthesis, and produces a rapid induction of START-specific transcripts, including CLN1 and CLN2. The ability of a nutritionally arrested cell to respond to cAMP is dependent on completion of the first process, and this is delayed in cells carrying a CLN3 deletion. Mating pheromone blocks the cAMP response but does not alter the process upstream of Ras-cAMP. These results suggest a model linking the Ras-cAMP pathway with regulation of G1 cyclin expression.

Blotting, Western↗
PubMed1993

Heat shock-mediated cell cycle blockage and G1 cyclin expression in the yeast Saccharomyces cerevisiae.

For cells of the yeast Saccharomyces cerevisiae, heat shock causes a transient inhibition of the cell cycle-regulatory step START. We have determined that this heat-induced START inhibition is accompanied by decreased CLN1 and CLN2 transcript abundance and by possible posttranscriptional changes to CLN3 (WHI1/DAF1) cyclin activity. Persistent CLN2 expression from a heterologous promoter or the CLN2-1 or CLN3-1 alleles that are thought to encode cyclin proteins with increased stability eliminated heat-induced START inhibition but did not affect other aspects of the heat shock response. Heat-induced START inhibition was shown to be independent of functions that regulate cyclin activity under other conditions and of transcriptional regulation of SWI4, an activator of cyclin transcription. Cells lacking Bcy1 function and thus without cyclic AMP control of A kinase activity were inhibited for START by heat shock as long as A kinase activity was attenuated by mutation. We suggest that heat shock mediates START blockage through effects on the G1 cyclins.

Cell Cycle↗