scholarly journals Expression of Alternatively Spliced RNA Transcripts of Amelogenin Gene Exons 8 and 9 and Its End Products in the Rat Incisor

2002 ◽  
Vol 50 (9) ◽  
pp. 1229-1236 ◽  
Author(s):  
Otto Baba ◽  
Nobuyuki Takahashi ◽  
Tatsuo Terashima ◽  
Wu Li ◽  
Pamela K. DenBesten ◽  
...  
Keyword(s):  
Enamel Matrix ◽  
Temporal Expression ◽  
Rat Incisor ◽  
Amelogenin Gene ◽  
Rna Transcripts ◽  
Alternatively Spliced ◽  
Exon 9 ◽  
Enamel Proteins ◽  
Tooth Germs

In addition to seven known exons of the amelogenin gene, recent studies have identified two exons downstream of amelogenin exon 7 in genomic DNA of mouse and rat. Here the spatial and temporal expression of mRNAs and of the translated proteins derived from alternative splicing of the amelogenin gene ending with exon 8 and exon 9 were examined by in situ hybridization (ISH) and immunohistochemistry (IHC). RNA signals for exons 8 and 9 were expressed in the ameloblast layer extending from early presecretory to postsecretory transitional stages of amelogenesis. IHC of amelogenin proteins that include sequences encoded by these exons demonstrated identical localization of these proteins in the ameloblast layer corresponding to RNA signals identified by ISH. There was intense immunostaining of the enamel matrix secreted by these cells. Western blotting analysis of rat enamel proteins revealed three distinct protein bands with sequences encoded by the new exons. These data confirmed the existence of the transcripts of alternatively spliced mRNAs coding for exons 8 and 9 of the amelogenin gene in rat tooth germs and suggest that the translated proteins contribute to the heterogeneity of amelogenins and have some significant roles in enamel formation and mineralization.

Gene Expression and Localization of Amelogenin in the Rat Incisor

1996 ◽  
Vol 10 (2) ◽  
pp. 201-207 ◽  
Author(s):  
T. Inage ◽  
H. Shimokawa ◽  
K. Wakao ◽  
S. Sasaki
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Maturation Stage ◽  
Enamel Matrix ◽  
Rat Incisor ◽  
Early Maturation ◽  
Incisal Edge ◽  
Enamel Epithelium ◽  
Developing Rat

Gene expression and localization of amelogenin were studied in the developing rat incisor by the methods of in situ hybridization and immunohistochemistry. ISH revealed the first expression of amelogenin mRNA in the inner enamel epithelium of the cervical loop. The signals were clearly observed in pre-ameloblasts in the region bordering on predentin formation and became more intense toward the cells on the initial enamel matrix secretion. The maximal signals were found in the cytoplasm of secretory ameloblasts. From the terminal secretion zone, the signals then became gradually weaker toward the incisal edge but were still evident in the cytoplasm of shortening, transitional ameloblasts and those at the early maturation stage. No signals were found in the cells of the stratum intermedium and stellate reticulum throughout amelogenesis. Immunohistochemistry by means of an antibody against amelogenin C-telopeptide consisting of 12 amino acids revealed immunoreaction in the secretory ameloblasts reacting to the ISH. When a polyclonal antibody against amelogenin was used, immunoreaction was found in the distal ends of ruffle-ended ameloblasts (RA) in the maturation zone. Those results indicated that amelogenin is synthesized by ameloblastic cells from the inner enamel epithelium to the early maturation stage and is then resorbed by the RA.

Studies on the Changes in Developing Enamel Caused By Ingestion of High Levels of Fluoride in the Rat

1987 ◽  
Vol 1 (2) ◽  
pp. 176-180 ◽  
Author(s):  
P.K. Denbesten ◽  
M.A. Crenshaw
Keyword(s):  
Enamel Organ ◽  
Maturation Stage ◽  
Careful Study ◽  
Enamel Matrix ◽  
Rat Incisor ◽  
Early Maturation ◽  
Enamel Proteins ◽  
And Control ◽  
Water Fluoride

Exposure to chronic high levels of fluoride results in the formation of fluorosed enamel. Although enamel may be more susceptible to fluorotic effects at certain stages of development, fluoride at sufficiently high levels may affect enamel at all stages of formation. Careful study of the changes in enamel caused by chronic fluoride ingestion is needed to understand more fully the mechanisms involved in the formation of fluorotic enamel. This paper discusses the various studies we have completed to define the changes, in developing enamel of the rat incisor, caused by long-term ingestion of fluoride in drinking water. Fluoride has been found to inhibit secretion of enamel proteins. Changes in the maturation stage of enamel formation include the retention of amelogenin proteins during early maturation. The various mechanisms which have been investigated in the formation of fluorosed enamel include a direct effect of fluoride on the enamel organ, and specific interactions of fluoride with the extracellular enamel matrix. Although the same amount of protease appears to be secreted in fluorosed and control enamel, a delay in the digestion of amelogenin protein occurs. This suggests that fluoride may directly or indirectly inhibit the protease present in fluorosed enamel to slow the proteolysis of amelogenins.

In situ hybridization to lampbrush chromosomes: a potential source of error exposed

1980 ◽  
Vol 41 (1) ◽  
pp. 115-123
Author(s):  
H.G. Callan ◽  
R.W. Old
Keyword(s):  
Lampbrush Chromosome ◽  
Single Pair ◽  
Lampbrush Chromosomes ◽  
Triturus Cristatus ◽  
Rna Transcripts ◽  
Potential Source ◽  
Source Of Error ◽  
Simple Sequence ◽  
Do So

Denatured 3H-labelled DNAs containing Xenopus or human globin sequences hybridize to RNA transcripts on a single pair of lateral loops on lampbrush chromosome IX of Triturus cristatus carnifex, and to no other loops on this chromosome or the rest of the complement. However they do so, not because of the globin sequences in the probes, but rather because the plasmids from which the probes were prepared were constructed with G.C homopolymer tails. Simple sequence poly d(C/G)n probes also hybridize with RNA transcripts on this same pair of loops, and with no others.

Correlation of Apical and Lateral Membrane Modulations of Maturation Ameloblasts

1985 ◽  
Vol 64 (8) ◽  
pp. 1055-1061 ◽  
Author(s):  
Z. Skobe ◽  
F. LaFrazia ◽  
K. Prostak
Keyword(s):  
Apical Membrane ◽  
Apical Cell ◽  
Matrix Proteins ◽  
Maturation Stage ◽  
Enamel Matrix ◽  
Enamel Matrix Proteins ◽  
Rat Incisor ◽  
Lateral Membrane ◽  
Apical Junctions ◽  
Scanning Electron

Maturation ameloblasts of rat incisor teeth have smooth-ended and ruffle-ended apical membrane configurations. It has also been reported that maturation ameloblasts have several lateral membrane configurations. The purpose of this study was to determine the correlation between the modulations of lateral and apical cell membranes of murine incisor ameloblasts in the maturation stage of amelogenesis. Maxillary and mandibular incisors were dissected, demineralized, embedded in paraffin, sectioned and then de-paraffinized, and the enamel organs were prepared for scanning electron microscopy. Additional mouse and rat incisor enamel organs were fixed and teased apart during dehydration, then observed in the SEM. The lengths of smooth- and ruffle-ended ameloblast segments were measured, and the site, length, and frequency of each lateral membrane configuration were determined within each segment. The lateral membrane configuration with folds forming from 12 to 14 channels around the periphery of the cells was most predominant in both smooth- and ruffle-ended cells. Cells surrounded by from six to eight channels were the only other lateral membrane configuration observed in ruffle-ended ameloblasts. Smooth-ended ameloblasts had lateral membrane configurations with either dense or sparse microvillous projections in addition to both types of channel cells. The observation that channelled extracellular spaces are always associated with ruffle-ended cells suggests that channels somehow function in conjunction with the ruffled apical membrane in resorption and removal of enamel matrix proteins. The smooth-ended ameloblasts lack tight apical junctions, and their microvillous lateral membranes permit the passage of plasma fluids around cells to the maturing enamel surface. Analysis of our data indicates that specific lateral membrane configurations are related to the type of apical membrane present.

Differential expression sites of TGF-β isoforms in chicken limb buds during morphogenesis

2005 ◽  
Vol 83 (4) ◽  
pp. 620-625 ◽  
Author(s):  
Shinya Aramaki ◽  
Fuminori Sato ◽  
Tomoki Soh ◽  
Nobuhiko Yamauchi ◽  
Masa-aki Hattori
Keyword(s):  
Limb Development ◽  
Developmental Stages ◽  
Polymerase Chain Reaction Analysis ◽  
Weak Signal ◽  
Temporal Expression ◽  
Chain Reaction ◽  
White Leghorn Chicken ◽  
Whole Mount ◽  
Polymerase Chain

TGF-β gene is expressed at various developmental stages and its principle role may be an involvement in organogenesis. The present study was performed to investigate the temporal expression of these TGF-β isoforms in the developing limb of White Leghorn Chicken, Gallus gallus (L., 1758). TGF-β isoforms were expressed in the developing limb as revealed by whole-mount in situ hybridization, but each showed a different pattern of expression. TGF-β2 was the dominant isoform compared with the other two isoforms. TGF-β2 first appeared along the proximodistal axis of the limb at stage 24 and condensed at the tip at stage 26. At stages 29–31, expression appeared in digits and then was extended to the interdigital spaces. A weak signal for TGF-β3 was first shown in the developing limb at stage 26, but there was no interdigital expression, unlike for TGF-β2. TGF-β4 was expressed in the developing limb at stage 26 and only in the interdigital spaces at stage 29. Reverse transcription – polymerase chain reaction analysis also showed that the transcript levels of TGF-β isoforms, especially TGF-β2, drastically increased at stage 29. These results suggest that TGF-β isoforms, with their patterns of expression, are specific regulatory factors that participate in limb development and digit morphogenesis.

Spatial- and temporal-restricted pattern for amelogenin gene expression during mouse molar tooth organogenesis

Development ◽  
1988 ◽  
Vol 104 (1) ◽  
pp. 77-85 ◽  
Author(s):  
M.L. Snead ◽  
W. Luo ◽  
E.C. Lau ◽  
H.C. Slavkin
Keyword(s):  
Gene Expression ◽  
In Situ Hybridization ◽  
Gene Transcription ◽  
Developmental Stages ◽  
Three Dimensional ◽  
Molar Tooth ◽  
Specific Expression ◽  
Amelogenin Gene ◽  
Stage Of Development

Position- and time-restricted amelogenin gene transcription was analysed in developing tooth organs using in situ hybridization with asymmetric complementary RNA probes produced from a cDNA specific to the mouse 26 × 10(3) Mr amelogenin. In situ analysis was performed on developmentally staged fetal and neonatal mouse mandibular first (M1) and maxillary first (M1) molar tooth organs using serial sections and three-dimensional reconstruction. Amelogenin mRNA was first detected in a cluster of ameloblasts along one cusp of the M1 molar at the newborn stage of development. In subsequent developmental stages, amelogenin transcripts were detected within foci of ameloblasts lining each of the five cusps comprising the molar crown form. The number of amelogenin transcripts appeared to be position-dependent, being more abundant on one cusp surface while reduced along the opposite surface. Amelogenin gene transcription was found to be bilaterally symmetric between the developing right and left M1 molars, and complementary between the M1 and M1 developing molars; indicating position-restricted gene expression resulting in organ stereoisomerism. The application of in situ hybridization to forming tooth organ geometry provides a novel strategy to define epithelial-mesenchymal signal(s) which are believed to be responsible for organ morphogenesis, as well as for temporal- and spatial-restricted tissue-specific expression of enamel extracellular matrix.

Immunoblot detection and expression of enamel proteins at the apical portion of the forming root in porcine permanent incisor tooth germs

2001 ◽  
Vol 19 (4) ◽  
pp. 236-243 ◽  
Author(s):  
Makoto Fukae ◽  
Takako Tanabe ◽  
Yasuo Yamakoshi ◽  
Marie Yamada ◽  
Yuko Ujiie ◽  
...  
Keyword(s):  
Incisor Tooth ◽  
Apical Portion ◽  
Enamel Proteins ◽  
Tooth Germs

scholarly journals Localization during development of alternatively spliced forms of cytotactin mRNA by in situ hybridization.

1990 ◽  
Vol 111 (2) ◽  
pp. 685-698 ◽  
Author(s):  
A L Prieto ◽  
F S Jones ◽  
B A Cunningham ◽  
K L Crossin ◽  
G M Edelman
Keyword(s):  
Nervous System ◽  
In Situ Hybridization ◽  
Blot Analysis ◽  
Radial Glia ◽  
Ventricular Zone ◽  
Mesenchymal Cells ◽  
Molecular Forms ◽  
Alternatively Spliced ◽  
The Brain

Cytotactin, an extracellular glycoprotein found in neural and nonneural tissues, influences a variety of cellular phenomena, particularly cell adhesion and cell migration. Northern and Western blot analysis and in situ hybridization were used to determine localization of alternatively spliced forms of cytotactin in neural and nonneural tissues using a probe (CT) that detected all forms of cytotactin mRNA, and one (VbVc) that detected two of the differentially spliced repeats homologous to the type III repeats of fibronectin. In the brain, the levels of mRNA and protein increased from E8 through E15 and then gradually decreased until they were barely detectable by P3. Among the three cytotactin mRNAs (7.2, 6.6, and 6.4 kb) detected in the brain, the VbVc probe hybridized only to the 7.2-kb message. In isolated cerebella, the 220-kD polypeptide and 7.2-kb mRNA were the only cytotactin species present at hatching, indicating that the 220-kD polypeptide is encoded by the 7.2-kb message that contains the VbVc alternatively spliced insert. In situ hybridization showed cytotactin mRNA in glia and glial precursors in the ventricular zone throughout the central nervous system. In all regions of the nervous system, cytotactin mRNAs were more transient and more localized than the polypeptides. For example, in the radial glia, cytotactin mRNA was observed in the soma whereas the protein was present externally along the glial fibers. In the telencephalon, cytotactin mRNAs were found in a narrow band at the edge of a larger region in which the protein was wide-spread. Hybridization with the VbVc probe generally overlapped that of the CT probe in the spinal cord and cerebellum, consistent with the results of Northern blot analysis. In contrast, in the outermost tectal layers, differential hybridization was observed with the two probes. In nonneural tissues, hybridization with the CT probe, but not the VbVc probe, was detected in chondroblasts, tendinous tissues, and certain mesenchymal cells in the lung. In contrast, hybridization with both probes was observed in smooth muscle and lung epithelium. Both epithelium and mesenchyme expressed cytotactin mRNA in varying combinations: in the choroid plexus, only epithelial cells expressed cytotactin mRNA; in kidney, only mesenchymal cells; and in the lung, both of these cell types contained cytotactin mRNA. These spatiotemporal changes during development suggest that the synthesis of the various alternatively spliced cytotactin mRNAs is responsive to tissue-specific local signals and prompt a search for functional differences in the various molecular forms of the protein.

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