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At least 19 recordsLinked to original sources
PubMed1988

Relationship between the levels of calbindin synthesis and calbindin mRNA in chick intestine. Quantitation of calbindin mRNA.

An RNA-excess filter hybridization assay was established to measure the absolute amount of calbindin mRNA in chick tissues. The tissue with the highest level of mRNA is intestine, followed by kidney and cerebellum; the mRNA was not detected in liver and skin. Calbindin mRNA in intestine and kidney is vitamin D-dependent. The maximum concentration of calbindin and its mRNA found after dosing vitamin D-deficient chicks with dihydroxyvitamin D3 (1,25-(OH)2D3) is less than 5% of that found with vitamin D dosing. Secondary 1,25-(OH)2D3 stimulation produced greatly increased amounts of both calbindin mRNA and the protein, at least reaching levels similar to those found after vitamin D dosing. In this last case, each mucosal cell contains about 2000 calbindin mRNA molecules which are translated at a rate sufficient to account for the levels of calbindin found. Calbindin mRNA is translated most rapidly in the very short time periods after its release into the cytoplasm. 1,25-(OH)2D3 has two effects on calbindin mRNA formation: first, to permit the expression of the calbindin gene and a second effect, of slower onset but more persistent, which increases either the rate of calbindin gene transcription or the stability of calbindin mRNA.

Animals↗
PubMed1991

Differential regulation by 1,25-dihydroxyvitamin D3 of calbindin-D9k and calbindin-D28k gene expression in mouse kidney.

The mouse kidney is a unique tissue since both vitamin D-dependent calcium binding proteins (calbindin-D9k and calbindin-D28k) are present in the same cells of the distal convoluted tubule. We have used specific complementary DNAs to mouse calbindin-D9k and mouse calbindin-D28k and Northern and slot blot analyses in order to obtain a better understanding of the regulation of two different molecular expressions of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] action in the same cells. Both calbindins were found to be regulated developmentally in a similar manner (an increase in gene expression between birth and 1 week of age, coinciding with nephron differentiation, and a peak at 3 weeks of age). However, the time course of response of the messenger RNA of each calbindin to 1,25(OH)2D3 was markedly different. The peak of induction of renal calbindin-D28k mRNA was at 12 h after a single injection of 1,25(OH)2D3 (200 ng/100 g body wt) to vitamin D-deficient mice, and a decrease was observed at 24 h (similar to the time course of response of other steroid-regulated genes). Interestingly, unlike calbindin-D28k, a delayed response of renal calbindin-D9k mRNA to 1,25(OH)2D3 was observed (the peak of induction was at 24 h after 1,25(OH)2D3 administration). Both genes in mouse kidney did not respond to glucocorticoids, although a dose-dependent decrease (12-86%) of mouse intestinal calbindin-D9k mRNA was observed after dexamethasone treatment, suggesting tissue-specific multiple steroid interactions in the regulation of calbindin gene expression. The finding of a different time course of regulation of each calbindin by 1,25(OH)2D3 suggests that different factors may be regulating the expression of the two different calbindins in mouse kidney and that elucidation of these control mechanisms should provide new insight concerning 1,25(OH)2D3-regulated gene expression.

Animals↗
PubMed1992

Time dependency of 1,25(OH)2D3 induction of calbindin mRNA and calbindin expression in chick enterocytes during their differentiation along the crypt-villus axis.

Quantitative methods of in situ hybridization and immunocytochemistry have been used to measure 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) induction of calbindin mRNA and calbindin protein expressed in jejunal enterocytes at all points along the crypt-villus axis over a 24 h period. Small amounts of calbindin mRNA detected in vitamin D3 deficient (D-deficient) chick intestine increased rapidly to maximal values 8 h after hormone injection. The magnitude of this response was inversely related to age of enterocyte measured separately by injecting tritiated thymidine into D-deficient and 1,25(OH)2D3-injected birds. Enterocytes of all ages expressed small amounts of calbindin 3 h after hormone injection. This amount of calbindin then increased up to 24 h after hormone injection. Maximal calbindin expression took place in basal villus enterocytes. Later decrease in the ability of upper villus enterocytes to express calbindin was associated with a similar fall in calbindin mRNA expression. Previously it was suggested that inefficient translation to calbindin mRNA might take place in basal villus enterocytes 48 h after vitamin D injection. Present work using 1,25 (OH)2D3 shows that calbindin expression takes place at a constant rate during this early stage of enterocyte development. Secondary events limiting higher rates of calbindin synthesis in upper crypt and basal villus enterocytes remain to be identified.

Animals↗
PubMed1992

Regulation of calbindin mRNA and calbindin turnover in intestine and shell gland of the chicken.

A synthetic oligonucleotide was used as a probe for measurement of calbindin mRNA in the shell gland and intestine of chickens. The half time of calbindin mRNA in the duodenum and shell gland was estimated at 2 and 3.6 h and that of calbindin at 13.9 and 32.6 h, respectively. The formation rates of calbindin mRNA were 0.37 and 0.17 pmol.h-1.g-1 and the rate of calbindin formation was 0.099 and 0.031 microgram.pmol mRNA-1.h-1 in the duodenum and shell gland, respectively. In the shell gland, calbindin mRNA and calbindin appeared at the time of sexual maturation during calcification of the first egg shell. Calbindin mRNA fluctuated markedly during the daily egg cycle, in close temporal association with egg shell calcification. When Ca2+ deposition was eliminated by expulsion of the ovum, the rise in calbindin mRNA was prevented. An indirect suppression of Ca2+ deposition by administration of the carbonic anhydrase inhibitor acetazolamide also resulted in a decrease in calbindin mRNA. The results are consistent with a possible role of Ca2+ flux in the regulation of calbindin mRNA appearance in the shell gland of chickens.

Animals↗
PubMed1991

Immunocytochemical localization of calbindin-D28k, calbindin-D9k and parvalbumin in rat kidney.

Possible sites involved in active Ca2+ transport were traced by means of immunocytochemical detection of calcium-binding proteins (CaBP) in the mammalian kidney. Antisera were raised in rabbits against calbindin-D28k from chick kidney and calbindin-D9k from bovine intestine and parvalbumin from rabbit muscle. In the rat kidney, parvalbumin and calbindin-D9k were co-localized in the loops of Henle and distal convoluted tubule. In the collecting duct their presence was restricted to the intercalated cells. In all responsive cells parvalbumin and calbindin-D9k were present exclusively along the basolateral membrane. Calbindin-D28k was only present in the outer part of the cortex, where it was localized in the distal convoluted tubule and in the connecting tubule. In these cells calbindin-D28k was evenly distributed through the cytosol. Calbindin-D28k, unlike parvalbumin and calbindin-D9k, could not be demonstrated in the loops of Henle or collecting duct.

Animals↗
PubMed1992

Distribution of calbindin D28k-like immunoreactivity (LI) in the monkey ventral horn: do Renshaw cells contain calbindin D28k-LI?

By use of indirect immunofluorescence and peroxidase-antiperoxidase immunohistochemistry, we show that the monkey (Macaca fascicularis) ventral horn harbors small- to medium-sized neurons in lamina VII as well as a dense network of fibers in laminae IX and VII that contain calbindin D28k (calbindin)-like immunoreactivity. The highest frequency of immunoreactive (IR) cell bodies was found at the levels of the cervical and lumbar intumescences. Furthermore, rostrocaudally oriented calbindin-IR fibers were encountered in the ventral and ventrolateral funiculi throughout the whole length of the cord, with the highest density at cervical and lumbar intumescences. Analysis at the EM level revealed calbindin-IR terminals in contact preferentially with dendrites of variable size and occasionally also large cell bodies, presumably belonging to motoneurons, in the lateral motor nucleus. The location of calbindin-IR neurons, as well as the distribution and ultrastructural characteristics of the calbindin-IR axonal system, makes it highly likely that these neurons are Renshaw cells that mediate recurrent inhibition to motoneurons.

Animals↗
PubMed1990

Localization of spot 35-calbindin (rat cerebellar calbindin) in the anterior pituitary of the rat: developmental and sexual differences.

Spot 35 protein is identical to rat brain calbindin, as based on the complete homology of their nucleotide sequence, and is named here as spot 35-calbindin. The immunoreactivity for this protein was first detected on embryonic Day 16 (E16) in the anterior pituitary anlages. As the development proceeded, spot 35-immunoreactive cells increased in number in the pars distalis, especially in its antero-ventral portion, and also pars tuberalis. No sex difference was noticed in the population density of the immunoreactive cells until postnatal Week 3. At postnatal Week 5 and thereafter through adulthood, spot 35-immunoreactive cells were much more numerous in the male anterior pituitary than in the female organ. All immunopositive cells for spot 35-calbindin contained secretory granules, and no folliculo-stellate cells were immunopositive. Any of the anterior pituitary hormones including ACTH, GH, LH, PRL and TSH could be simultaneously expressed with spot 35-calbindin in the granulated cells. Based on the ultrastructure of the secretory granules, spot 35-immunoreactive cells were classified into four types: cells containing round granules, 350 nm; those containing granules of irregular contour larger than 350 nm; those containing small granules, up to 150 nm; and those containing a mixture of the round large and small granules. Cells containing large round granules were dominant in males, while cells containing small granules were dominant in females. The functional significance of spot 35-calbindin in the anterior pituitary is briefly discussed.

Animals↗
PubMed1988

Rat brain calbindin D28: six domain structure and extensive amino acid homology with chicken calbindin D28.

Calbindin D28 cDNA clones were isolated from a rat brain library using a chicken intestinal Calbindin D28 cDNA probe. Nucleotide sequence analysis of these clones shows an open reading frame of 78 nucleotide coding for a 261 amino acid 29,994 dalton protein. The predicted amino acid sequence contains six repeats of a domain with the feature of an EF-hand calcium binding site. In domains II and VI, two of the five oxygen-containing amino acids important for the coordination of calcium are absent, suggesting that these two sites have lost their calcium-binding capability. Comparing the amino acid sequence to that recently reported for the chicken Calbindin D28 there is 79% homology. Tolerating conservative differences, the homology increases to 93%. Interestingly, domains II and VI which have presumably lost their calcium binding ability are very conserved among the two species (81% and 78%, respectively). Since an EF hand calcium binding site requires only certain types of amino acids at certain positions, rather than a specific amino acid sequence, maintaining a calcium binding site is a weak conservation pressure. To explain the high degree of homology of rat and chicken Calbindin D28, and in particular the conservation of the two degenerated domains over the 300 million years since divergence of birds and mammals, additional function(s) of the Calbindin D28 are postulated.

Amino Acid Sequence↗
PubMed1991

Molecular basis for co-operativity in Ca2+ binding to calbindin D9k. 1H nuclear magnetic resonance studies of (Cd2+)1-bovine calbindin D9k.

The molecular basis for the co-operativity in binding of calcium ions by bovine calbindin D9k has been addressed by carrying out a comparative analysis of the solution conformation and dynamics of the apo, half saturated and fully saturated species using two-dimensional 1H nuclear magnetic resonance spectroscopy. Since the half saturated calcium form of the protein is not significantly populated under equilibrium conditions due to the co-operativity in binding of calcium ions, the half saturated cadmium form of the protein has been substituted for the calcium form. To verify that cadmium forms of calbindin D9k represent viable models for the calcium-bound species, the fully saturated cadmium form has been prepared and compared to the calcium-saturated protein. Virtually complete 1H resonance assignments have been obtained for both the (Cd2+)1 and the (Cd2+)2 states. Secondary structure elements and the global folding pattern were determined from nuclear Overhauser effects, backbone spin-spin coupling constants and slowly exchanging amide protons. Comparisons of the half saturated protein with the apo and calcium-saturated forms of calbindin D9k show that all three structures are highly similar. However, a change in the structural and dynamic properties of the protein does occur upon binding of the first ion; the half saturated form is found to be more similar to the calcium-saturated form than to the apo form. These results have important implications concerning the molecular basis for the co-operativity, and suggest that entropic effects associated with the protein dynamics play an important role.

Amino Acid Sequence↗
PubMed1988

Molecular cloning of mammalian 28,000 Mr vitamin D-dependent calcium binding protein (calbindin-D28K): expression of calbindin-D28K RNAs in rodent brain and kidney.

We report the isolation of a cloned cDNA for the mammalian 28,000 Mr vitamin D-dependent calcium binding protein (calbindin-D28K; CaBP28K) by immunological screening of a lambda gt11 bacterial expression library. The library contained cDNAs copied from poly(A)RNA of adult mouse cerebellum. We confirmed the identity of the CaBP28K cDNA by comparing its DNA sequence with that of chick CaBP28K cDNA. In the coding region, 79% of the mouse cDNA sequence was identical to the reported sequence of CaBP28K cDNA derived from chicken intestine. Rat brain and kidney each contain three species of poly(A)RNA that hybridize to CaBP28K cDNA--a major species of 1.9 kb, and rarer components of 2.8 kb and 3.2 kb. All three RNAs appear to be transcribed from a single gene. The ratios of these CaBP28K RNAs were the same in brain and kidney. In the cerebellum, in situ hybridization reveals that CaBP28K RNAs are confined to Purkinje neurons.

Animals↗
PubMed1992

Ontogeny of calbindin-D28K and calbindin-D9K in the mouse kidney, duodenum, cerebellum and placenta.

The appearance of the calcium-binding proteins (CaBP-D28K and CaBP-D9K) in embryonic mice tissues was determined using a sensitive immunohistochemical assay. CaBP-D28K first appears in myenteric nerve plexuses of the duodenum on day E15, in duodenal villus cells on day E16, in Purkinje cells of the cerebellum on day E19, in cells of the mesonephric duct on day E11 and in the metanephric duct on day E12. CaBP-D9K first appears in enterocytes of the duodenum on day E18, in trophoblastic giant cells (TGC) of the placenta on day E10, and in the metanephric duct on day E15. A differential time of appearance and colocalization of the two CaBPs is demonstrated in the embryonic mouse kidney, suggesting either that vitamin D does not control both CaBPs in the foetus or that the vitamin D control is unequal. The early appearance and location of CaBP-D9K in TGCs may suggest that these cells play an important role in transplacental transfer of calcium.

Animals↗
PubMed1992

Heterogeneous development of calbindin-D28K expression in the striatal matrix.

In the present study, we attempted to trace the development of the striatal matrix by analyzing the ontogenetic expression of calbindin-D28K (calbindin), a calcium binding protein selectivity expressed in medium-sized neurons of the matrix compartment of the mature rat's caudoputamen. The localization of calbindin was documented in a series of developing rat brains, as was the compartmental location of these cells relative to tyrosine hydroxylase (TH)-immunostained dopamine islands, sites of future striosomes. Medium-sized striatal neurons appeared in the striatum at embryonic day (E) 20, and from their first appearance, the calbindin-positive neurons had highly heterogeneous distributions. They first formed a latticework of patches and bands in a ventral region of the caudoputamen. By postnatal day (P) 7, this early calbindin-positive lattice had evolved into a mosaic in which circumscript pockets of low calbindin-like immunoreactivity appeared in more extensive calbindin-rich surrounds. With further development, the mosaic gradually encroached on all but the dorsolateral caudoputamen, a district that is calbindin-poor at adulthood. A special lateral branch of the striatal calbindin system was also identified, distinct from the rest of the calbindin-positive mosaic in several developmental characteristics. In the parts of the caudoputamen where the developing calbindin system and dopamine island system were both present, the dopamine islands invariably lay in calbindin-poor zones. Most dopamine islands, however, only filled parts of the corresponding calbindin-poor zones. Moreover, there were some calbindin-poor zones for which TH-positive dopamine islands could not be detected. Thus during development, calbindin was expressed in the extrastriosomal matrix of the striatum, but the matrix could be divided into calbindin-rich and calbindin-poor zones. In the calbindin-rich regions, there were patches of especially intense calbindin expression and zones of weaker expression. These results suggest that there is neurochemical heterogeneity in the striatal matrix during the prolonged developmental period in which the early calbindin-positive lattice expands to form the calbindin-positive matrix of the mature striatum. Surprisingly, calbindin expression in the matrix, although eventually distributed in strictly complementary fashion to striosomes, does not originate as a system complementary to dopamine islands. The prolonged disparity between the borders of dopamine islands and calbindin-poor zones, and the different spatiotemporal schedules of development of the islands and the calbindin gaps suggest instead that the final match between the borders of striosomes and surrounding matrix results from dynamic processes occurring early in postnatal development. Candidate mechanisms for the gradual adjustment of these borders are proposed.

Aging↗
PubMed1992

Transient calbindin-D28k-positive systems in the telencephalon: ganglionic eminence, developing striatum and cerebral cortex.

Calbindin-D28k (calbindin) is a member of the superfamily of calcium-binding proteins implicated in the regulation of intracellular calcium. In the mature brain, calbindin is widely expressed in neurons of the forebrain and the hindbrain, and in the telencephalon calbindin-like immunoreactivity is particularly strongly expressed by medium-sized neurons of the striatum and by certain other neurons in the cortex and subcortex. We have traced the development of calbindin expression in the forebrain of the rat, and report here that in addition to the steady development of these calbindin-positive neuronal systems, transient waves of calbindin expression occur in cells of the ventricular zones of the basal ganglia and cortex and in cells of the telencephalic regions derived from these ventricular zones including radial glia of the developing striatum. In the striatum and its ventricular zone (the ganglionic eminence, or GE) we identified four transient calbindin-positive systems in the perinatal period. First, calbindin-immunoreactive cells began to appear in the GE by embryonic day (E)18, and by E20 an extensive dorsal and lateral part of the GE was marked by dense calbindin-like immunoreactivity in the ventricular zone. This calbindin system peaked at postnatal day (P)0-P3 and disappeared by P15. Its presence suggests that the GE is divisible on a molecular basis into lateral and medial districts that may correspond to derivatives of the lateral and medial ventricular ridges. Second, a system of calbindin-positive processes appeared in the dorsal and lateral caudoputamen with temporal and spatial distributions matching the germinal zone system. Many of these processes could be traced from calbindin-positive cells in the ventricular zone of the GE, including processes stretching across the full width of the dorsal caudoputamen. Double-staining experiments demonstrated that these radial processes were Rat.401-positive, suggesting that they form a subset of radial glia in the developing telencephalon. These findings demonstrate that during development calbindin is expressed in glial as well as neural cells. They further suggest that the radial glia associated with the GE form heterogeneous populations, the transient calbindin-positive radial glia being associated with the lateral ridge of the GE and its derivatives. Third, a scattered population of calbindin-positive cells with morphologies different from the common medium-sized calbindin-immunoreactive neurons of the striatum appeared in the dorsal and lateral striatum from about E20 to P15. Some of these cells were close to the transient calbindin-positive radial processes in the same region, but others were not.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1991

Redistribution of calbindin-D28k in chick intestine in response to calcium transport.

Vitamin D and its hormonally active metabolite 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] are known to alter several parameters associated with stimulated intestinal Ca2+ transport: levels of calbindin-D28K, tubulin, and endosomal-lysosomal organelles containing Ca2+, and calbindin-D28K. In the present study the as yet unexamined relationship among Ca2+ transport, calbindin-D28K, and microtubules was studied by immunofluorescence microscopy. In vitamin D3-treated or 1,25-(OH)2D3-treated chicks, in the absence of Ca2+ transport, immunofluorescence microscopy of intestinal tissue fixed at 25 C indicated a colocalization of calbindin-D28K and tubulin along epithelial cell brush border and basal-lateral membranes. Initiation of in situ Ca2+ absorption for 10, 20, or 30 min before tissue fixation resulted first in increased punctate calbindin-D28K staining and then in a progressive decrease in intestinal cell- and microtubule-associated calbindin-D28K, with a concomitant increase in calbindin-D28K labeling in the villus core. When intestinal tissue from 1,25-(OH)2D3-treated chicks was chilled to 4 C before fixation (a procedure shown by others to cause microtubule depolymerization), evaluation by immunofluorescence microscopy revealed diffuse cytoplasmic staining of both the immunoreactive tubulin and its associated calbindin-D28K. These results indicate the possible involvement of calbindin-D28K with tubulin during the process of Ca2+ transport and the secretion of the calbindin-D28K as a consequence of the overall transport process. Electron microscopy with immunogold labeling revealed intestinal epithelial calbindin-D28K to be localized inside of small vesicles and lysosome-like structures, with sparse cytoplasmic labeling. Subsequent electron microscopic analysis of intestinal epithelial microtubules prepared by polymerization and depolymerization revealed immunogold labeling in coprecipitated vesicular remnants, with consistently light staining of filaments traversing segments of the microtubules. In biochemical studies, isolation of intestinal microtubules or tubulin by three distinct procedures revealed increasing levels of associated calbindin-D28K as a function of time after 1,25-(OH)2D3 repletion of vitamin D-deficient chicks. Addition of calbindin-D28K to intestinal microtubules isolated from vitamin D-deficient chicks exhibited saturable binding when exogenous calbindin-D28K reached levels comparable to those present in vitamin D-replete chick intestine. Collectively, these results suggest that calbindin-D28K is predominantly located in membrane-delimited vesicles, with a very minor component associated with filamentous elements that can be isolated with tubulin and microtubules. Additionally, calbindin-D28K is dynamically involved in Ca2+ transport in the intestine.

Animals↗
PubMed1991

Modulation of quail intestinal and egg shell gland calbindin (Mr 28,000) gene expression by vitamin D3, 1,25-dihydroxyvitamin D3 and egg laying.

The effects of vitamin D3 sources, egg production and egg cycle on the genomic expression of calbindin (Mr 28,000) in the intestine and egg shell gland (ESG) of quail were characterized by Northern blot and solution hybridization, using synthetic oligonucleotide probe. In vitamin D3- or 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3)-fed quail, onset of egg production induced duodenal and ESG calbindin mRNA and calbindin synthesis. Duodenal calbindin mRNA was slightly higher during the period of shell calcification as compared with the period during which shells were not formed (ESG inactivity). ESG calbindin mRNA was markedly higher during the period of shell calcification than of ESG inactivity. Increasing dietary intake of [3H]1 alpha-hydroxyvitamin D3 increased the duodenal, but not ESG, content of 1,25-(OH)2D3 and calbindin. Duodenal calbindin and its mRNA were absent in vitamin D-deficient quail and were not affected by egg laying. ESG calbindin in the vitamin D-deficient quail was not affected by egg laying, but calbindin mRNA increased in the vitamin D-deficient birds during shell calcification. The results suggest that: (a) intestinal calbindin mRNA and calbindin are induced and/or regulated, either directly or indirectly, by 1,25-(OH)2D3; (b) intestinal calbindin and its mRNA are further induced at the onset of egg laying by an additional stimulator besides 1,25-(OH)2D3; (c) 1,25-(OH)2D3 is required for the expression of the latter stimulator; (d) ESG calbindin mRNA and calbindin are induced in egg-laying birds by a stimulator associated with the egg cycle; and (e) the induction of ESG calbindin mRNA does not need vitamin D metabolites, but 1,25-(OH)2D3 is required for the translation of the mRNA.

Animals↗
PubMed1988

Analysis of rat vitamin D-dependent calbindin-D28k gene expression.

We report the use of a cloned cDNA for mammalian calbindin-D28k (28-kDa vitamin D-dependent calcium-binding protein) to study the expression of the rat calbindin gene. Tissue distribution studies, using Northern analysis, indicated that calbindin-D28k-mRNA is detected in rat kidney and brain but is not detected in rat intestine, testes, bone, pancreas, liver, lung, or skeletal muscle. Both rat kidney and brain contain three RNA species (1.9, 2.8, and 3.2 kilobase pairs). The regulation of the gene was characterized by both Northern and slot blot analysis. Hormonal regulation, developmental expression of calbindin-D28k-mRNA, and the effect of dietary alteration were examined. In the kidney all three species of mRNA were dependent on the presence of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) for their induction. The time course of induction of renal calbindin-D28k-mRNA indicated that a significant increase in calbindin-D-mRNA was detectable as early as 2 h following a single injection of 1,25-(OH)2D3 (200 ng/100 g of body weight), reaching a maximum at 12 h. Unlike the kidney high levels of calbindin-D28k-mRNA were observed in the brain of vitamin D-deficient rats. The concentration of calbindin-D28k-mRNA in brain was unchanged after 1,25-(OH)2D3 administration. Developmental studies indicated that calbindin-D-mRNA in rat kidney and brain is present prior to birth but is developmentally regulated in a tissue-specific manner. The most pronounced changes in the abundance of renal calbindin-D28k-mRNA occur between birth and 1 week of age. Unlike the kidney a large increase in brain calbindin-D28k-mRNA occurs at a later time, between 1 and 2 weeks of age (the period of major synapse formation). In dietary alteration studies results of Northern blot analysis indicate that low dietary phosphorus results in increased calbindin-D-mRNA in kidney but not in brain. These studies represent the first analysis of the rat calbindin-D28k gene and its regulation in vivo. Our findings suggest that in rat kidney and brain there are significant differences both in the expression of the gene for calbindin-D28k and its regulation by 1,25-(OH)2D3.

Aging↗
PubMed1989

Increases in calbindin D 28K mRNA in the uterus of the domestic fowl induced by sexual maturity and shell formation.

Uterine concentrations of calbindin D 28K mRNA were measured in immature pullets and laying hens by dot-blot hybridization using a [32P]cRNA probe prepared from the calbindin cDNA. In immature pullets, estrogen increased the calbindin mRNA level and the plasma concentration of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. When testosterone was administered with estrogen there was a further increase in calbindin and its mRNA and an increase in the free 1,25-(OH)2D3 index calculated as the ratio of the molar concentrations of total 1,25-(OH)2D3 and vitamin D-binding protein (DBP). In laying hens the uterine concentration of calbindin mRNA was low 4 hr after ovulation, but increased most markedly 12 and 18 hr later, when shell calcification took place. Calbindin concentration remained unchanged during the different stages of egg formation but was much higher in laying hens than in pullets treated with sex steroids. Suppression of shell formation by premature expulsion of the egg decreased the concentrations of calbindin mRNA and uterine calbindin and the free 1,25-(OH)2D3 index in the plasma. A concomitant increase in calbindin and its mRNA was observed at resumption of shell formation in hens previously laying shell-less eggs. Withdrawal of food for 44 hr decreased the uterine concentration of calbindin and its mRNA without a change in the free 1,25-(OH)2D3 index in the blood. It is concluded that the synthesis of uterine calbindin is stimulated primarily at sexual maturity and at calcification of the first shell by transcriptional processes. The daily increase in calbindin mRNA associated with shell formation and the absence of a concomitant change in calbindin concentration suggest that post-transcriptional processes exist and that stimuli other than the sex steroid or the 1,25-(OH)2D3 are involved in regulation of calbindin synthesis in the uterus.

Animals↗
PubMed1990

Modulation of chick intestinal and renal calbindin gene expression by dietary vitamin D3, 1,25-dihydroxyvitamin D3, calcium and phosphorus.

Synthetic oligonucleotide probes complementary to chick calbindin-28 kDa-mRNA were used to study the latter's regulation and relationship to calbindin in the chick. The effects of vitamin D3 sources and dietary alteration on the genomic expression were characterized by Northern blot and solution hybridization. Intestinal calbindin and its mRNA were almost absent in vitamin D-deficient chicks and were not affected by dietary alteration. Renal calbindin and its mRNA were lower in the vitamin D-deficient than in vitamin D3- or 1,25-dihydroxyvitamin D3 (1,25(OH)2D3)-fed chicks. In the same animal, renal calbindin mRNA and calbindin were higher than intestinal. In vitamin D3-fed chicks, dietary calcium (Ca) or phosphorus (P) restriction induced, and high dietary Ca inhibited, intestinal calbindin and its mRNA synthesis. In the same chicks, dietary P restriction induced renal calbindin mRNA and calbindin synthesis. In 1,25-(OH)2D3-fed chicks, dietary P restriction induced and high dietary Ca inhibited the synthesis of intestinal and renal calbindin. The results suggest that: (a) most of the changes in renal and intestinal calbindin could be attributed to the changes in the mRNA; (b) the adaptation to dietary Ca and P alterations requires vitamin D metabolites; (c) high dietary Ca affects intestinal and renal calbindin-mRNA and calbindin via mechanisms independent of kidney 1-hydroxylase; and (d) plasma Ca and renal calbindin or its mRNA tend to change together in vitamin D-deficient or vitamin D3-fed, but not in 1,25(OH)2D3-fed chicks.

Animals↗