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M Taoka

Publications and source records attributed to M Taoka.

At least 19 recordsLinked to original sources
PubMed2002

Processing of tactile and kinesthetic signals from bilateral sides of the body in the postcentral gyrus of awake monkeys.

Earlier studies pointed out that in the primary somatosensory cortex (SI) the receptive fields (RF) of bilateral neurons were related exclusively to the body midline. We recently found a substantial number of neurons with bilateral RFs on hand digits, shoulders/arms or legs/feet in the caudalmost part (areas 2 and 5) of the postcentral gyrus in awake macaque monkeys. The RFs of these neurons were generally of the most complex types found in this region of the cortex, and thus they were considered to be at the highest level along the hierarchical chain of information processing. We conclude that there are two types of bilateral RFs in the postcentral gyrus, one representing the midline structures such as the intraoral cavity, chin or trunk and the other related to limb structures such as fingers, hands, arms, shoulders, legs and girdles. Functional significance of the bilateral activity could be understood in behavioral context as it is seen more extensively in the body parts where bilateral coordination is essential.

Animals↗
PubMed2001

Human glycosaminoglycan glucuronyltransferase I gene and a related processed pseudogene: genomic structure, chromosomal mapping and characterization.

Here we describe the characterization of the human glycosaminoglycan glucuronyltransferase I gene (GlcAT-I) and a related pseudogene. The GlcAT-I gene was localized to human chromosome 11q12-q13 by in situ hybridization of metaphase chromosomes. GlcAT-I spanned 7 kb of human genomic DNA and was divided into five exons. Northern blot analysis showed that GlcAT-I exhibited ubiquitous but markedly different expressions in the human tissues examined. The GlcAT-I promoter was approx. 3-fold more active in a melanoma cell line than in a hepatoma cell line, providing evidence for the differential regulation of the gene's expression. Stepwise 5' deletions of the promoter identified a strong enhancer element between -303 and -153 bp that included binding motifs for Ets, CREB (cAMP-response-element-binding protein) and STAT (signal transducers and activators of transcription). Screening of a human genomic library identified one additional distinct genomic clone containing an approx. 1.4 kb sequence region that shared an overall 95.3% nucleotide identity with exons 1-5 of GlcAT-I. However, a lack of intron sequences, as well as the presence of several nucleotide mutations, insertions and deletions that disrupted the potential GlcAT-I reading frame, suggested that the clone contained a processed pseudogene. The pseudogene was localized to chromosome 3. The human genome therefore contains two related GlcAT-I genes that are located on separate chromosomes.

Base Sequence↗
PubMed2001

The complexity of receptive fields of periodontal mechanoreceptive neurons in the postcentral area 2 of conscious macaque monkey brains.

The representation of the oral structures in area 2 of the postcentral somatosensory cortex was studied in conscious macaque monkeys by recording single-neuron activities. A total of 58 penetrations were made in the oral region of five hemispheres in three animals and 707 neurons were isolated. The receptive field characteristics were identified for 480 neurons. Among them, 62 neurons along 21 penetrations responded to mechanical tooth stimulation (periodontal mechanoreceptive neurons). The overwhelming majority (81%, 50/62) of periodontal mechanoreceptive neurons had receptive fields on several teeth in either jaw. Moreover, six had receptive fields on corresponding maxillary and mandibular teeth. Thirty-seven percent (23/62) of periodontal mechanoreceptive neurons also had receptive fields on other oral structures surrounding the teeth, such as gingiva (16/23), lip (10/23), and tongue mucosa (1/23). Among them, four neurons had receptive fields on both the gingiva and lip. These receptive field features were readily interpreted as a combination of the regions stimulated simultaneously during food intake. We therefore speculated that these periodontal mechanoreceptive neurons in area 2 may be the prerequisite neural substrate for the eventual oral stereognosis that will take place in the neighboring association cortices. The coexistence of periodontal mechanoreceptive neurons with simple and complex receptive fields, or small and large receptive fields in the oral region of the postcentral area 2 suggests that this region could be the stage for the integration of sensory information from the periodontal ligament and from other oral structures.

Animals↗
PubMed2001

Serum amino-terminal propeptide of type III procollagen and 7S domain of type IV collagen correlate with hepatic iron concentration in patients with chronic hepatitis C following alpha-interferon therapy.

BACKGROUND: It has been reported that chronic infection with hepatitis C virus is associated with excess iron deposits in the liver of subjects who are neither alcoholics nor recipients of blood transfusions. However, little is known about the relationship between hepatic iron concentration (HIC) and the serum levels of hepatic fibrogenesis markers, which were caused by interferon therapy for chronic hepatitis C. Therefore, changes in the serum amino-terminal propeptide of type III procollagen (P-III-P) and the 7S domain of type IV collagen (7S-IV) in 16 patients treated with alpha-interferon (IFN-alpha) were studied, and their HIC and histological assessment evaluated. Hepatic iron concentrations were measured by using liver biopsy specimens obtained before and 6 months after the cessation of treatment. METHODS AND RESULTS: Eight subjects (50%) who had normal alanine transaminase levels at 6 months after therapy showed significantly lowered HIC, and attenuated hepatic iron staining with decreased serum levels of P-III-P and 7S-IV compared to the remaining subjects. The HIC was significantly correlated with the serum levels of P-III-P and 7S-IV in all subjects. CONCLUSIONS: These findings suggest that IFN-alpha treatment may decrease stimuli for fibrogenesis, at least in part, by reducing the hepatic iron deposition in patients with chronic hepatitis C.

Adult↗
PubMed2001

Programmed filtration, a new method for removing large molecules and regulating albumin leakage during hemodiafiltration treatment.

During hemodiafiltration (HDF) treatment for chronic renal failure patients, replacing large volumes using high-flux membranes with relatively large pores is preferred from the standpoint of enhancing the elimination of large molecules (10 to 50 kd). Aggressive protein-permeable treatment often results in massive leakage of essential albumin, however, which may cause fatigue, hypotension, and a decrease in the plasma albumin concentration in some patients. During 5-hour conventional HDF treatment with the filtration rate or pressure set at constant values, fractional albumin loss in the dialysate was assayed, which revealed that the albumin concentration in the dialysate showed a maximum value in the beginning with a steep decline within 1 hour. Approximately 40% to 50% of the total amount of albumin leakage occurred during the first 30 minutes. Concomitantly the large molecules transferred into the pores by aggressive filtration during the beginning partially plugged the pores, resulting in a decrease in the permeability for beta(2)-microglobulin. From the standpoint of achieving the highest clearance for large molecules, while suppressing albumin leakage below the acceptable range, the optimal profiles for filtration conditions in HDF have been proposed, in which either the transmembrane pressure is regulated according to the sigmoid curve in the pressure control manner or the flow rate is set along the concave in the flow control manner. The profiles of pressure or flow as a function of time have been programmed and installed in a HDF machine to perform an optimal HDF treatment automatically. The new filtration methods gave significantly higher beta(2)-microglobulin removal and lower albumin leakage than conventional HDF methods with constant filtration.

Albumins↗
PubMed2001

Bilateral activity and callosal connections in the somatosensory cortex.

Earlier studies recording single neuronal activity in the postcentral somatosensory cortex of monkeys converged in suggesting that the bilateral receptive fields were related exclusively to the body midline including the trunk, perioral face, and oral cavity. These neurons were recorded mostly in the rostral part of the gyrus, areas 3b and 1. However, the authors recently found a substantial number of neurons with bilateral receptive fields on extremities, hand/digits, shoulders/arms, or legs/feet in the caudalmost part (areas 2 and 5) of the postcentral gyrus. The authors review these results and discuss functional implications of the bilateral representation in the postcentral somatosensory cortex.

Animals↗
PubMed2000

Profiling of Caenorhabditis elegans proteins using two-dimensional gel electrophoresis and matrix assisted laser desorption/ionization-time of flight-mass spectrometry.

The nematode Caenorhabditis elegans (C. elegans) is the first animal whose whole 97 Mb genome sequence, encoding ca. 19000 open reading frames (ORF's), has been essentially determined. We tried to establish a 2-DE map of the nematode proteome by means of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). A soluble protein fraction of mixed stages of the worm, wild-type strain N2, was applied to 2-D PAGE. After Coomassie Brilliant Blue (CBB) staining, 1200 spots were detected and 140 major spots were excised from the gel and subjected to in-gel digestion with Achromobacter protease I (lysyl endopeptidase). Resulting peptides were analyzed by matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) followed by peptide mass fingerprinting for protein identification. With this approach we have obtained a two-dimensional electrophoresis (2-DE) protein map in which 69 spots were localized as landmarks for comparison of expression profiles to elucidate the basis of various biological events.

Animals↗
PubMed2000

Protein profiling of rat cerebella during development.

Protein profiles of developing rat cerebella were analyzed by means of two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS). The analysis of adult rat cerebellum gave rise to a protein map comprising approximately 3000 spots detectable by silver staining following high resolution 2-DE with a pH range of 3-10 and a mass range of 8-100 kDa. To obtain landmarks for comparison of developmental profiles of cerebellar proteins, 100 spots were subjected to peptide mass fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and 67 spots were assigned on the map. Analysis of profiles of the developing cerebella revealed significant changes in the expression of proteins during development. In most cases the expression levels of proteins increased as the cerebellum matured, while the expression of 42 spots appeared specific or remarkably abundant in the immature cerebellum. Peptide mass fingerprinting of these spots allowed us to identify 29 proteins, which include, in addition to proteins of unknown function, many proteins known to have roles in the development of the central nervous system. These results suggest that the proteomic approach is valuable for mass identification of proteins involved in cerebellar morphogenesis.

Animals↗
PubMed2000

Matrix assisted laser desorption/ionization-time of flight-mass spectrometry analysis of proteins detected by anti-phosphotyrosine antibody on two-dimensional-gels of fibrolast cell lysates after tumor necrosis factor-alpha stimulation.

We describe efficient methods for using functional proteomics analysis to study signal transduction pathways in murine fibroblast L929 cells following stimulation with tumor necrosis factor (TNF)-alpha. After stimulation with TNF-alpha, cellular proteins of L929 cells were extracted with a lysis buffer containing 0.3% sodium dodecyl sulfate (SDS) for 10-30 min time intervals, and were separated by two-dimensional (2-D) electrophoresis followed by immunoblot analysis with anti-phosphotyrosine antibody and alkaline phosphatase-anti IgG antibody conjugate. To improve detection sensitivity by immunoblot analysis we used a chemifluorescent substrate for alkaline phosphatase. One hundred protein spots were detected in the TNF-alpha stimulated L929 cell extract by immunoblot analysis. The use of chemifluorescence allowed us to quantitate immunoblotted spots with fluoroscanner so that we were able to detect time-dependent changes of a number of immunoblotted spots. Protein spots on a silver-stained 2-D gel corresponding to those detected by immunoblot analysis were subjected to in-gel trypsin digestion- matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)-mass spectrometry analysis, respectively. Twenty-one proteins detected by immunoblot analysis were identified by MS-Fit database search analysis. Among them, the proteins that show time-dependent changes in staining intensity include vimentin, tubulin beta-chain, eukaryotic translation initiation factor 1A, chromatin assembly factor 1 (P48 subunit), probable protein disulfide isomerase P5, and several other proteins. Vimentin and tubulin beta-chain have been reported to be phosphorylated at tyrosine residues and involved in the signal transduction pathway induced by TNF-alpha. However, the other proteins have no previously known function in the signal transduction pathway. Thus, the methods used in this study seem to be suitable for the identification of time-dependent changes in many proteins that are involved in signal transduction. Usefulness of the method for comprehensive analysis of the proteins involved in signal transduction pathway and the limitations of the method are discussed.

Acrylic Resins↗
PubMed2000

Bilateral receptive field neurons in the hindlimb region of the postcentral somatosensory cortex in awake macaque monkeys.

Single-neuron activities were recorded in the hindlimb region of the primary somatosensory cortex and part of area 5 in awake Japanese monkeys. A total of 1050 units were isolated from five hemispheres of four animals. Receptive fields (RFs) and submodalities were identified for 90% of isolated neurons in areas 3a and 3b. The percentage decreased as the recoding site moved to the more caudal areas. Deep or skin submodality neurons were dominant in area 3a or area 3b, respectively. Deep submodality neurons increased in more caudal areas and were the majority in areas 2 and 5. These observations were consistent with those in the hand and/or digit or arm and/or trunk region. The identified neurons were classified by their RF positions into four types: the foot, leg, foot and leg, or hindlimb and other body parts type. Among 831 identified neurons, 33 neurons had bilateral RFs, 14 had ipsilateral RFs, and the rest (N=784) had contralateral RFs. The relative incidence of neurons with bilateral or ipsilateral RFs among identified neurons was less than 1% in areas 3a, 3b, and 1, and 16% or 25% in areas 2 or 5, respectively. Within areas 2 and 5, the percentage of neurons with bilateral or ipsilateral RFs was significantly smaller in the foot type (5%) than in other RF types (24-57%). RFs of the foot type were on the sole or single toe but never on multiple toes. These observations contrasted with the previous findings that neurons with bilateral RFs were more frequently seen in the hand and/or digit region and that RFs on multiple digit tips were dominant there. The present study thus demonstrated that neurons with bilateral RFs do exist in the hindlimb region. Similarly to the forelimb region, they were found mostly in areas 2 and 5, the caudalmost areas of the postcentral gyrus and hierarchically higher stages in information processing. The relative paucity of neurons with bilateral RFs on the foot, especially those with RFs on multiple toes, may reflect functional differences between the foot and the hand.

Action Potentials↗
PubMed1999

Stimulus-coupled interaction of tyrosine hydroxylase with 14-3-3 proteins.

Tyrosine hydroxylase (TH) is phosphorylated by CaM kinase II and is activated in situ in response to a variety of stimuli that increase intracellular Ca(2+). We report here, using baculovirus-expressed TH, that the 14-3-3 protein binds and activates the expressed TH when the enzyme is phosphorylated at Ser-19, a site of CaM kinase II-dependent phosphorylation located in the regulatory domain of TH. Site-directed mutagenesis showed that a TH mutant in which Ser-19 was substituted by Ala retained enzymatic activity at the same level as the non-mutated enzyme, but was a poor substrate for CaM kinase II and did not bind the 14-3-3 protein. Likewise, a synthetic phosphopeptide (FRRAVpSELDA) corresponding to the part of the TH sequence, including phosphoSer-19, inhibited the interaction between the expressed TH and 14-3-3, while the phosphopeptide (GRRQpSLIED) corresponding to the site of cAMP-dependent phosphorylation (Ser-40) had little effect on complex formation. The complex was very stable with a dissociation constant of 3 nM. Furthermore, analysis of PC12nnr5 cells transfected with myc-tagged 14-3-3 showed that 14-3-3 formed a complex with endogenous TH when the cultured cells were exposed to a high K(+) concentration that increases intracellular Ca(2+) and phosphorylation of Ser-19 in TH. These findings suggest that the 14-3-3 protein participates in the stimulus-coupled regulation of catecholamine synthesis that occurs in response to depolarization-evoked, Ca(2+)-dependent phosphorylation of TH.

14-3-3 Proteins↗
PubMed1998

Representation of the midline trunk, bilateral arms, and shoulders in the monkey postcentral somatosensory cortex.

Single neuronal activities were recorded in the arm/trunk region of the postcentral gyrus in awake Japanese monkeys. A total of 1608 units were isolated from four hemispheres of two animals, and receptive fields (RFs) and submodalities were identified in 1162 units. Deep or skin submodality neurons were dominant in area 3a or area 3b, respectively. The deep/skin ratio increased as the recording site moved from area 3b to the more caudal areas. In areas 3a and 3b, neuronal RFs were almost exclusively on either the arm or trunk. In areas 2 and 5, neurons with RFs on the trunk decreased and those with RFs on the hand or covering more than one body part, etc. increased. We found a total of 107 neurons with bilateral RFs and 56 with ipsilateral RFs, while the rest (n=999) were with contralateral RFs. Bilateral or ipsilateral neurons of skin submodality (n=37) were found in areas 1, 2, and 5. Twenty six (70%) had RFs on the trunk and/or occiput, five on the forelimb, and the rest (n=6) on both the trunk and forelimb (the combined type). Among 33 skin bilateral neurons, 90% (n=30) had RFs across the midline. Bilateral or ipsilateral neurons responding to joint manipulation (n=104) were found in areas 2 and 5. Most of them were activated by manipulation of the shoulder and/or elbow (the proximal type, n=72, 69%). There were 25 neurons of the combined type (both the proximal and distal joints were effective, 24%). Bilateral or ipsilateral neurons of deep-others submodality (n=20) were found in areas 1, 2, and 5. The forelimb type (n=12, 60%) was dominant in this category. The combined-type neurons in both the skin- and joint-manipulation categories were found only or mostly in area 5. These results indicate the presence of hierarchical processing for bilateral as well as contralateral information within the arm/trunk region of the postcentral gyrus.

Animals↗
PubMed1997

14-3-3 protein binds to insulin receptor substrate-1, one of the binding sites of which is in the phosphotyrosine binding domain.

Insulin binding to its receptor induces the phosphorylation of cytosolic substrates, insulin receptor substrate (IRS)-1 and IRS-2, which associate with several Src homology-2 domain-containing proteins. To identify unique IRS-1-binding proteins, we screened a human heart cDNA library with 32P-labeled recombinant IRS-1 and obtained two isoforms (epsilon and zeta) of the 14-3-3 protein family. 14-3-3 protein has been shown to associate with IRS-1 in L6 myotubes, HepG2 hepatoma cells, Chinese hamster ovary cells, and bovine brain tissue. IRS-2, a protein structurally similar to IRS-1, was also shown to form a complex with 14-3-3 protein using a baculovirus expression system. The amount of 14-3-3 protein associated with IRS-1 was not affected by insulin stimulation but was increased significantly by treatment with okadaic acid, a potent serine/threonine phosphatase inhibitor. Peptide inhibition experiments using phosphoserine-containing peptides of IRS-1 revealed that IRS-1 contains three putative binding sites for 14-3-3 protein (Ser-270, Ser-374, and Ser-641). Among these three, the motif around Ser-270 is located in the phosphotyrosine binding domain of IRS-1, which is responsible for the interaction with the insulin receptor. Indeed, a truncated mutant of IRS-1 consisting of only the phosphotyrosine binding domain retained the capacity to bind to 14-3-3 protein in vivo. Finally, the effect of 14-3-3 protein binding on the insulin-induced phosphorylation of IRS-1 was investigated. Phosphoamino acid analysis revealed that IRS-1 coimmunoprecipitated with anti-14-3-3 antibody to be weakly phosphorylated after insulin stimulation, on tyrosine as well as serine residues, compared with IRS-1 immunoprecipitated with anti-IRS-1 antibody. Thus, the association with 14-3-3 protein may play a role in the regulation of insulin sensitivity by interrupting the association between the insulin receptor and IRS-1.

14-3-3 Proteins↗
PubMed1996

Increased level of neurokinin-1 tachykinin receptor gene expression during early postnatal development of rat brain.

Substance P is known to elicit diverse actions via activating multiple subtypes of tachykinin receptors, and these actions appear to be involved not only in synaptic transmission but also in synaptic plasticity during development of the mammalian central nervous system. The availability of sensitive quantitation of individual tachykinin receptor subtypes is crucial for elucidating the physiological function specifically mediated by activation of a particular receptor subtype. We thus attempted to develop an assay to determine the level of messenger RNA molecule encoding the neurokinin-1-type tachykinin receptor and apply it for assessment of developmental changes in the neurokinin-1 receptor gene expression in the rat brain to explore the role of tachykinin receptors during ontogeny. The assay was designed to use a competitive reverse transcription-polymerase chain reaction co-amplifying endogenous neurokinin-1 receptor messenger RNA and internal standard, which enabled specific quantification of the number of neurokinin-1 receptor transcripts, ranging from 3.1 x 10(3) to 1.3 x 10(5) molecules/microgram total RNA. The levels of neurokinin-1 receptor gene expression were examined in three different brain regions of the rat aged 0-56 days after birth. The order of neurokinin-1 receptor messenger RNA expression was hippocampus > cerebral cortex > > cerebellum at all ages examined except postnatal day 0, where its expression was more abundant in the cerebral cortex than in the hippocampus. From postnatal day 3 onward, the hippocampus contained 140-160% of the cortical levels. Although the tachykinin receptor expression in the cerebellum was too low to be accurately assessed by conventional techniques, our assay enabled us to determine the amount of cerebellar neurokinin-1 receptor messenger RNA that changed in the range 7-23% of the cortical level during postnatal development. A prominent feature revealed by this assay is that the neurokinin-1 receptor gene expression in the rat brain is developmentally regulated. The hippocampus displayed a transient peak of neurokinin-1 receptor messenger RNA at postnatal day 3 and a subsequent gradual decrease. In the cerebral cortex, the amount of the message was highest at birth, and was followed by a moderate decrease during postnatal development. At 56 days after birth, the expression levels in both brain regions were down-regulated to approximately 50% of their maximal levels. The transitory pattern of gene expression was also observed in the cerebellum. The results of this study demonstrate that the reverse transcription-polymerase chain reaction-based assay is useful to quantitate precisely the neurokinin-1 tachykinin receptor message in limited tissue samples derived from discrete brain regions. Together with previous findings, the increased level of neurokinin-1 receptor messenger RNA expression in immature rat brain shown by the present analysis suggests that the neurokinin-1-type tachykinin receptor may play a role in the synaptic plasticity associated with morphological and functional development of the mammalian CNS.

Aging↗
PubMed1996

Changes in the gene expression of a protein with the cdc10/SWI6 motif, V-1, during rat follicular development and corpus luteum formation.

We examined the gene expression of V-1, a novel soluble protein with the cdc10/SWI6 motif, in pseudopregnant rat ovaries. Northern blot analysis on days 1, 5, and 11 of pseudopregnancy revealed an approximately 2-fold increase in the V-1 messenger RNA (mRNA) expression level on day 5 to that on day 1, and no significant change was observed between those on day 5 and day 11. An injection of human CG on days 5 further increased th V-1 mRNA level to about 1.6-fold of that of the untreated control. Western blot analysis showed higher V-1 protein expression on days 5 and 11 of pseudopregnancy than that on day 1. In situ hybridization and immunohistochemistry with ovaries on day 3 of pseudopregnancy showed that luteal cells of corpora lutea and also cells of the coexisting follicles including oocytes express V-1 mRNA and the protein, with apparent rank order of the expression: oocytes > luteal cells > follicular cells >> atretic follicular cells including oocytes. These data indicate the dynamic change in the V-1 gene expression in the ovarian steroidogenic cells and oocytes and suggest potential roles of the V-1 protein in ovarian functions including corpus luteum formation and folliculogenesis.

Animals↗
PubMed1994

A nuclear factor containing the leucine-rich repeats expressed in murine cerebellar neurons.

A nuclear protein, termed leucine-rich acidic nuclear protein (LANP), has been isolated from among rat cerebellar proteins whose expression was transiently increased during an early stage of postnatal development. The amino acid sequence, deduced from its cDNA, showed that LANP contains 247 amino acids consisting of two distinct structural domains: the N-terminal domain characterized by "leucine-rich repeat," which is found in many eukaryotic proteins and which potentially functions in mediating protein-protein interactions, and the C-terminal domain characterized by a cluster of acidic amino acids with a putative nuclear localization signal. Immunohistochemical study using an antibody against LANP revealed that the protein is localized mainly in nuclei of Purkinje cells. In the rat cerebellum on postnatal day 7, LANP mRNA was expressed moderately in the external granule and Purkinje cells and weakly in the internal granule cells. The expression in these cells, especially in Purkinje cells, increased in the second postnatal week and thereafter decreased to an adult level. The structural characteristics, localization, and the stage- and cell type-specific expression suggest a potential role of LANP in a signal transduction pathway that directs differentiation of cerebellar neurons.

Aging↗
PubMed1994

Murine cerebellar neurons express a novel gene encoding a protein related to cell cycle control and cell fate determination proteins.

We cloned cDNAs of a novel protein (designated V-1) that has been identified from among the developmentally regulated proteins in the rat cerebellum. Protein sequencing analysis (Taoka, M., Yamakuni, T., Song, S.-Y., Yamakawa, Y., Seta, K., Okuyama, T., and Isobe, T. (1992) Eur. J. Biochem. 207, 615-620) and cDNA sequence analysis revealed that the V-1 protein consists of 117 amino acids and contains 2.5 contiguous repeats of the cdc10/SWI6 motif, which was originally found in the products of the cell cycle control genes of yeasts and the cell fate determination genes in Drosophila and Caenorhabditis elegans. In situ hybridization histochemistry revealed that the expression of the V-1 gene is transiently increased in postmigratory granule cells during postnatal rat cerebellar development and thereafter is markedly suppressed, whereas Purkinje cells constitutively express V-1 mRNA. In contrast, cerebellar granule cells of the staggerer mutant mouse continue to express the V-1 gene even when the granule cells of the normal mouse have ceased to express the V-1 gene, suggesting that the expression of the V-1 gene in granule cells is regulated through the interaction with Purkinje cells. On the basis of these results, we postulate that the V-1 protein has a potential role in the differentiation of granule cells.

Amino Acid Sequence↗