scholarly journals Neural regulation of muscle acetylcholine receptor epsilon- and alpha-subunit gene promoters in transgenic mice.

1993 ◽  
Vol 123 (6) ◽  
pp. 1535-1544 ◽  
Author(s):  
K Gundersen ◽  
J R Sanes ◽  
J P Merlie
Keyword(s):  
Acetylcholine Receptor ◽  
Fusion Gene ◽  
Transgenic Animals ◽  
Alpha Subunit ◽  
Gene Promoters ◽  
Promoter Sequences ◽  
Epsilon Subunit ◽  
Synaptic Region ◽  
Localization Signal ◽  
Activity Dependence

The effects of denervation were investigated in mice with transgenes containing promoter elements from the muscle acetylcholine receptor epsilon- and alpha-subunit genes. The promoter sequences were coupled to a nuclear localization signal-beta-galactosidase fusion gene (nlacZ) as a reporter. While many postsynaptic specializations form in the embryo, expression of the epsilon subunit is induced during the first two postnatal weeks. When muscles were denervated at birth, before the onset of epsilon expression, epsilon nlacZ still appeared at the former synaptic sites on schedule. This result suggests that the nerve leaves a localized "trace" in the muscle that can continue to regulate transcription. An additional finding was that epsilon nlacZ expression was much stronger in denervated than in intact muscles. This suggests that the epsilon promoter is similar to the other subunits in containing elements that are activated on cessation of neural activity. However, even after denervation, epsilon nlacZ expression was always confined to the synaptic region whereas alpha nlacZ expression increased in nuclei along the entire length of the fiber. This suggests that while the epsilon gene is similar in its activity dependence to other subunit genes, it is unique in that local nerve-derived signals are essential for its expression. Consequently, inactivity enhances epsilon expression only in synaptic nuclei where such signals are present, but enhances expression throughout the muscle fiber. Truncations and an internal deletion of the epsilon promoter indicate that cis-elements essential for the response to synaptic signals are contained within 280 bp of the transcription start site. In contrast to these results in young animals, denervation in older animals leads to an unexpected reduction in nlacZ activity. However, mRNA measurements indicated that transgene expression was increased in these animals. This discordance between nlacZ mRNA and enzyme activity, demonstrates a previously unknown limitation of nlacZ as a reporter gene in transgenic animals.

Synapse-specific expression of acetylcholine receptor genes and their products at original synaptic sites in rat soleus muscle fibres regenerating in the absence of innervation

Development ◽  
1992 ◽  
Vol 116 (1) ◽  
pp. 41-53 ◽  
Author(s):  
H.R. Brenner ◽  
A. Herczeg ◽  
C.R. Slater
Keyword(s):  
Acetylcholine Receptor ◽  
Basal Lamina ◽  
Neuromuscular Junctions ◽  
Muscle Fibres ◽  
Northern Blots ◽  
Specific Expression ◽  
Epsilon Subunit ◽  
Synaptic Region ◽  
Rat Soleus Muscle

To test the hypothesis that synaptic basal lamina can induce synapse-specific expression of acetylcholine receptor (AChR) genes, we examined the levels mRNA for the alpha- and epsilon-subunits of the AChR in regenerating rat soleus muscles up to 17 days of regeneration. Following destruction of all muscle fibres and their nuclei by exposure to venom of the Australian tiger snake, new fibres regenerated within the original basal lamina sheaths. Northern blots showed that original mRNA was lost during degeneration. Early in regeneration, both alpha- and epsilon-subunit mRNAs were present throughout the muscle fibres but in situ hybridization showed them to be concentrated primarily at original synaptic sites, even when the nerve was absent during regeneration. A similar concentration was seen in denervated regenerating muscles kept active by electrical stimulation and in muscles frozen 41–44 hours after venom injection to destroy all cells in the synaptic region of the muscle. Acetylcholine-gated ion channels with properties similar to those at normal neuromuscular junctions were concentrated at original synaptic sites on denervated stimulated muscles. Taken together, these findings provide strong evidence that factors that induce the synapse-specific expression of AChR genes are stably bound to synaptic basal lamina.

scholarly journals Three possible disulfides in the acetylcholine receptor alpha-subunit.

1988 ◽  
Vol 263 (2) ◽  
pp. 1017-1022
Author(s):  
R Mosckovitz ◽  
J M Gershoni
Keyword(s):  
Acetylcholine Receptor ◽  
Alpha Subunit ◽  
Receptor Alpha

Meiotic expression of human ornithine transcarbamylase in the testes of transgenic mice

1988 ◽  
Vol 8 (4) ◽  
pp. 1821-1825
Author(s):  
K A Kelley ◽  
J W Chamberlain ◽  
J A Nolan ◽  
A L Horwich ◽  
F Kalousek ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Fusion Gene ◽  
Regulatory Region ◽  
Transgenic Animals ◽  
Ornithine Transcarbamylase ◽  
Regulatory Sequences ◽  
Base Pairs ◽  
Protein Coding ◽  
Wide Range ◽  
Flanking Sequences

In an attempt to use mouse metallothionein-I (mMT-I) regulatory sequences to direct expression of human ornithine transcarbamylase in the liver of transgenic animals, fusion genes joining either 1.6 kilobases or 185 base pairs of the mMT-I regulatory region to the human ornithine transcarbamylase protein-coding sequence were used to produce transgenic mice. In mice carrying the fusion gene with 1.6 kilobases of the mMT-I 5'-flanking sequences, transgene expression was observed in a wide range of tissues, but, unexpectedly, expression in liver was never observed. Surprisingly, in mice carrying the fusion gene regulated by only 185 base pairs of the mMT-I 5'-flanking sequences, the transgene was expressed exclusively in male germ cells during the tetraploid, pachytene stage of meiosis.

Human globin gene promoter sequences are sufficient for specific expression of a hybrid gene transfected into tissue culture cells

1987 ◽  
Vol 7 (1) ◽  
pp. 398-402
Author(s):  
T Rutherford ◽  
A W Nienhuis
Keyword(s):  
Gene Expression ◽  
Globin Gene ◽  
Gene Promoter ◽  
Gene Promoters ◽  
Globin Genes ◽  
Specific Expression ◽  
Tissue Specific ◽  
Promoter Sequences ◽  
Erythroleukemia Cells ◽  
Murine Erythroleukemia

The contribution of the human globin gene promoters to tissue-specific transcription was studied by using globin promoters to transcribe the neo (G418 resistance) gene. After transfection into different cell types, neo gene expression was assayed by scoring colony formation in the presence of G418. In K562 human erythroleukemia cells, which express fetal and embryonic globin genes but not the adult beta-globin gene, the neo gene was expressed strongly from a fetal gamma- or embryonic zeta-globin gene promoter but only weakly from the beta promoter. In murine erythroleukemia cells which express the endogenous mouse beta genes, the neo gene was strongly expressed from both beta and gamma promoters. In two nonerythroid cell lines, human HeLa cells and mouse 3T3 fibroblasts, the globin gene promoters did not allow neo gene expression. Globin-neo genes were integrated in the erythroleukemia cell genomes mostly as a single copy per cell and were transcribed from the appropriate globin gene cap site. We conclude that globin gene promoter sequences extending from -373 to +48 base pairs (bp) (relative to the cap site) for the beta gene, -385 to +34 bp for the gamma gene, and -555 to +38 bp for the zeta gene are sufficient for tissue-specific and perhaps developmentally specific transcription.

Synaptic basal lamina contains a signal for synapse-specific transcription

Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 673-680 ◽  
Author(s):  
S.A. Jo ◽  
S.J. Burden
Keyword(s):  
Acetylcholine Receptor ◽  
Basal Lamina ◽  
Motor Nerve ◽  
Receptor Gene ◽  
High Rate ◽  
Denervated Muscle ◽  
Transcriptional Pattern ◽  
Synaptic Region ◽  
Acetylcholine Receptor Gene ◽  
Continuous Presence

Nuclei in the synaptic region of multinucleated skeletal myofibers are transcriptionally distinct, since acetylcholine receptor genes are transcribed at a high rate by these nuclei, but not by nuclei elsewhere in the myofiber. Although this spatially restricted transcription pattern is presumably imposed by the motor nerve, the continuous presence of the nerve is not required, since synapse-specific transcription persists after denervation. These results suggest either that a transcriptional signal persists at synaptic sites after nerve terminals have degenerated, or that a transcriptional pattern in the myofiber, once established, is stable in the absence of a nerve-derived signal. To distinguish between these possibilities, we denervated muscle and damaged the myofibers and specialized cells located near synaptic sites, and then studied transcription of an acetylcholine receptor gene in myofibers that regenerated in their original basal lamina sheaths, but remained denervated. We show that synapse-specific transcription is re-induced in these regenerated myofibers, and we conclude that a signal for synapse-specific transcription is stably maintained in the synaptic basal lamina.

Introduction of a porcine growth hormone fusion gene into transgenic pigs promotes growth

1988 ◽  
Vol 90 (2) ◽  
pp. 295-300
Author(s):  
P.D. Vize ◽  
A.E. Michalska ◽  
R. Ashman ◽  
B. Lloyd ◽  
B.A. Stone ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Fusion Gene ◽  
Transgenic Animals ◽  
Growth Hormone Gene ◽  
Gene Sequences ◽  
Transgenic Pigs ◽  
Gene Construct ◽  
Metallothionein Promoter

Six transgenic pigs have been produced by microinjecting a human metallothionein promoter/porcine growth hormone gene construct into the pronuclei of fertilized eggs which were transferred to synchronized recipient sows. The resulting transgenic animals contained between 0.5 and 15 copies of the gene construct per cell, and at least one of the animals expressed the introduced gene and grew at an increased rate compared to both transgenic and non-transgenic littermates. Some of the transgenic animals that did not appear to grow at increased rates were found to contain rearranged gene sequences. Two of the transgenic pigs have been shown to pass on the introduced genes to their offspring.

Promoter and enhancer elements from the rat elastase I gene function independently of each other and of heterologous enhancers

1987 ◽  
Vol 7 (10) ◽  
pp. 3466-3472
Author(s):  
D M Ornitz ◽  
R E Hammer ◽  
B L Davison ◽  
R L Brinster ◽  
R D Palmiter
Keyword(s):  
Fusion Gene ◽  
Leukemia Virus ◽  
Human Growth ◽  
Cell Types ◽  
Regulatory Elements ◽  
Pancreatic Acinar Cells ◽  
Gene Promoters ◽  
Base Pairs ◽  
Metallothionein Gene ◽  
Rat Elastase

An elastase-human growth hormone (hGH) fusion gene containing 205 base pairs of elastase 5' flanking region is expressed exclusively in pancreatic acinar cells of transgenic mice. This paper shows that the promoter region (-72 to +8) and the enhancer (-205 to -73) function independently of each other. The elastase enhancer can activate the heterologous mouse metallothionein gene and the hGH gene promoters; conversely, enhancers from the thymocyte-specific murine leukemia virus MCF13 and the metal regulatory elements from the metallothionein gene can activate the elastase promoter in a variety of cell types. Combinations of immunoglobulin and elastase enhancers with a heterologous promoter and the hGH gene result in expression in all of the tissues predicted by the sum of each enhancer acting alone. Thus these enhancer elements act independently of each other, suggesting that they do not have silencing activity in cells in which they are normally inactive.

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