Sequence and Chromosomal Context Effects on Variegated Expression of Keratin 5/lacZ Constructs in Stratified Epithelia of Transgenic Mice

Genetics ◽  
2001 ◽  
Vol 158 (1) ◽  
pp. 341-350
Author(s):  
Angel Ramírez ◽  
Eric Milot ◽  
Immaculada Ponsa ◽  
Camelia Marcos-Gutiérrez ◽  
Angustias Page ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Long Range ◽  
Copy Number ◽  
Context Effects ◽  
Integration Site ◽  
Chromosomal Integration ◽  
Lacz Expression ◽  
Keratin 5 ◽  
Transgenic Lines ◽  
Stratified Epithelia

Abstract The expression of transgene loci in mammals often occurs in a heterocellular fashion resulting in variegated patterns of expression. We have examined the effect of chromosomal integration site, copy number, and transcriptionally activating sequences on the variegation of a keratin 5-lacZ (K5Z) construct in the stratified epithelia of transgenic mice. lacZ expression in these mice is always mosaic, and the β-gal activity per cell is usually higher in the lines with a higher proportion of expressing cells. Similar constructs, in which cDNAs were exchanged by lacZ sequences, showed no variegation. Also, when a strongly active, nonvariegating construct was coinjected with K5Z, most transgenic lines showed an almost homogeneous lacZ expression. The comparison of transgene arrays of different copies inserted at the same locus (obtained by using a lox/Cre system) showed that the reduction of copy number does not lead to an increase in the proportion of cells that express the transgene. Finally, in most of the variegating or nonexpressing lines the transgenes were located both at intermediate positions and at peritelomeric regions in the long chromosome arms. These findings suggest that the probability and efficiency of expression of K5Z genes depend on both long range chromosomal influences and on sequences in the transgene array.

A minimal c-fes cassette directs myeloid-specific expression in transgenic mice

Blood ◽  
2000 ◽  
Vol 96 (9) ◽  
pp. 3040-3048
Author(s):  
Ahlke Heydemann ◽  
Soren Warming ◽  
Cynthia Clendenin ◽  
Kirsten Sigrist ◽  
J. Peter Hjorth ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Dna Sequences ◽  
Copy Number ◽  
Messenger Rna ◽  
Transgene Expression ◽  
Fluorescent Protein ◽  
Control Function ◽  
Integration Site ◽  
Myeloid Cells ◽  
Independent Copy

The c-fes proto-oncogene encodes a 92-kd protein tyrosine kinase whose expression is restricted largely to myeloid and endothelial cells in adult mammals. A 13.2-kilobase (kb) humanc-fes genomic fragment was previously shown to containcis-acting element(s) sufficient for a locus control function in bone marrow macrophages. Locus control regions (LCRs) confer transgene expression in mice that is integration site independent, copy number dependent, and similar to endogenous murine messenger RNA levels. To identify sequences required for this LCR,c-fes transgenes were analyzed in mice. Myeloid-cell–specific, deoxyribonuclease-I–hypersensitive sites localized to the 3′ boundary of exon 1 and intron 3 are required to confer high-level transgene expression comparable to endogenous c-fes, independent of integration site. We define a minimal LCR element as DNA sequences (nucleotides +28 to +2523 relative to the transcription start site) located within intron 1 to intron 3 of the human locus. When this 2.5-kb DNA fragment was linked to a c-fes complementary DNA regulated by its own 446–base-pair promoter, integration-site–independent, copy-number–dependent transcription was observed in myeloid cells in transgenic mice. Furthermore, this 2.5-kb cassette directed expression of a heterologous gene (enhanced green fluorescent protein) exclusively in myeloid cells. The c-fes regulatory unit represents a novel reagent for targeting gene expression to macrophages and neutrophils in transgenic mice.

scholarly journals Alu sequence involvement in transcriptional insulation of the keratin 18 gene in transgenic mice.

1993 ◽  
Vol 13 (11) ◽  
pp. 6742-6751 ◽  
Author(s):  
I S Thorey ◽  
G Ceceña ◽  
W Reynolds ◽  
R G Oshima
Keyword(s):  
Transgenic Mice ◽  
Rna Polymerase ◽  
Copy Number ◽  
Integration Site ◽  
Rna Polymerase Iii ◽  
Flanking Sequence ◽  
Polymerase Iii ◽  
Alu Sequence ◽  
Flanking Sequences ◽  
Keratin 18

The human keratin 18 (K18) gene is expressed in a variety of adult simple epithelial tissues, including liver, intestine, lung, and kidney, but is not normally found in skin, muscle, heart, spleen, or most of the brain. Transgenic animals derived from the cloned K18 gene express the transgene in appropriate tissues at levels directly proportional to the copy number and independently of the sites of integration. We have investigated in transgenic mice the dependence of K18 gene expression on the distal 5' and 3' flanking sequences and upon the RNA polymerase III promoter of an Alu repetitive DNA transcription unit immediately upstream of the K18 promoter. Integration site-independent expression of tandemly duplicated K18 transgenes requires the presence of either an 825-bp fragment of the 5' flanking sequence or the 3.5-kb 3' flanking sequence. Mutation of the RNA polymerase III promoter of the Alu element within the 825-bp fragment abolishes copy number-dependent expression in kidney but does not abolish integration site-independent expression when assayed in the absence of the 3' flanking sequence of the K18 gene. The characteristics of integration site-independent expression and copy number-dependent expression are separable. In addition, the formation of the chromatin state of the K18 gene, which likely restricts the tissue-specific expression of this gene, is not dependent upon the distal flanking sequences of the 10-kb K18 gene but rather may depend on internal regulatory regions of the gene.

A minimal c-fes cassette directs myeloid-specific expression in transgenic mice

Blood ◽  
2000 ◽  
Vol 96 (9) ◽  
pp. 3040-3048 ◽  
Author(s):  
Ahlke Heydemann ◽  
Soren Warming ◽  
Cynthia Clendenin ◽  
Kirsten Sigrist ◽  
J. Peter Hjorth ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Dna Sequences ◽  
Copy Number ◽  
Messenger Rna ◽  
Transgene Expression ◽  
Fluorescent Protein ◽  
Control Function ◽  
Integration Site ◽  
Myeloid Cells ◽  
Independent Copy

Abstract The c-fes proto-oncogene encodes a 92-kd protein tyrosine kinase whose expression is restricted largely to myeloid and endothelial cells in adult mammals. A 13.2-kilobase (kb) humanc-fes genomic fragment was previously shown to containcis-acting element(s) sufficient for a locus control function in bone marrow macrophages. Locus control regions (LCRs) confer transgene expression in mice that is integration site independent, copy number dependent, and similar to endogenous murine messenger RNA levels. To identify sequences required for this LCR,c-fes transgenes were analyzed in mice. Myeloid-cell–specific, deoxyribonuclease-I–hypersensitive sites localized to the 3′ boundary of exon 1 and intron 3 are required to confer high-level transgene expression comparable to endogenous c-fes, independent of integration site. We define a minimal LCR element as DNA sequences (nucleotides +28 to +2523 relative to the transcription start site) located within intron 1 to intron 3 of the human locus. When this 2.5-kb DNA fragment was linked to a c-fes complementary DNA regulated by its own 446–base-pair promoter, integration-site–independent, copy-number–dependent transcription was observed in myeloid cells in transgenic mice. Furthermore, this 2.5-kb cassette directed expression of a heterologous gene (enhanced green fluorescent protein) exclusively in myeloid cells. The c-fes regulatory unit represents a novel reagent for targeting gene expression to macrophages and neutrophils in transgenic mice.

scholarly journals Alu sequence involvement in transcriptional insulation of the keratin 18 gene in transgenic mice

1993 ◽  
Vol 13 (11) ◽  
pp. 6742-6751
Author(s):  
I S Thorey ◽  
G Ceceña ◽  
W Reynolds ◽  
R G Oshima
Keyword(s):  
Transgenic Mice ◽  
Rna Polymerase ◽  
Copy Number ◽  
Integration Site ◽  
Rna Polymerase Iii ◽  
Flanking Sequence ◽  
Polymerase Iii ◽  
Alu Sequence ◽  
Flanking Sequences ◽  
Keratin 18

The human keratin 18 (K18) gene is expressed in a variety of adult simple epithelial tissues, including liver, intestine, lung, and kidney, but is not normally found in skin, muscle, heart, spleen, or most of the brain. Transgenic animals derived from the cloned K18 gene express the transgene in appropriate tissues at levels directly proportional to the copy number and independently of the sites of integration. We have investigated in transgenic mice the dependence of K18 gene expression on the distal 5' and 3' flanking sequences and upon the RNA polymerase III promoter of an Alu repetitive DNA transcription unit immediately upstream of the K18 promoter. Integration site-independent expression of tandemly duplicated K18 transgenes requires the presence of either an 825-bp fragment of the 5' flanking sequence or the 3.5-kb 3' flanking sequence. Mutation of the RNA polymerase III promoter of the Alu element within the 825-bp fragment abolishes copy number-dependent expression in kidney but does not abolish integration site-independent expression when assayed in the absence of the 3' flanking sequence of the K18 gene. The characteristics of integration site-independent expression and copy number-dependent expression are separable. In addition, the formation of the chromatin state of the K18 gene, which likely restricts the tissue-specific expression of this gene, is not dependent upon the distal flanking sequences of the 10-kb K18 gene but rather may depend on internal regulatory regions of the gene.

scholarly journals The human leukocyte integrin CD11a promoter directs expression in leukocytes of transgenic mice

Blood ◽  
1995 ◽  
Vol 86 (1) ◽  
pp. 147-155 ◽  
Author(s):  
KA Ritchie ◽  
A Aprikian ◽  
KA Gollahon ◽  
DD Hickstein
Keyword(s):  
Transgenic Mice ◽  
Copy Number ◽  
Integration Site ◽  
Human Leukocyte ◽  
Regulatory Sequences ◽  
Start Site ◽  
Transcription Start ◽  
Transgene Copy Number ◽  
Dependent Activity ◽  
Gene Transcription Start Site

The human CD11a molecule is expressed specifically on lymphocytes, monocyte/macrophages, and neutrophils, in which it mediates important adhesion-related functions. We used 1.7 kb of regulatory sequences upstream from the human CD11a gene transcription start site to drive expression of a modified human CD4 reporter gene in transgenic mice. The transgene was expressed in a tissue-specific fashion on all leukocytes and paralleled endogenous mouse CD11a expression. All five founder mice expressed the transgene, providing evidence for integration site-independent expression. However, expression was not proportional to transgene copy number. These studies indicate that (1) the mutated human CD4 serves as an excellent reporter for analysis of leukocyte-specific promoters; (2) the CD11a regulatory unit used here represents a novel reagent for targeting gene expression to leukocytes; and (3) additional regulatory regions will be required for copy-number- dependent activity of CD11a regulatory sequences.

scholarly journals Genome-wide integration site detection using Cas9 enriched amplification-free long-range sequencing

2020 ◽  
Author(s):  
Joost van Haasteren ◽  
Altar M Munis ◽  
Deborah R Gill ◽  
Stephen C Hyde
Keyword(s):  
Long Range ◽  
Insertional Mutagenesis ◽  
Lentiviral Vector ◽  
Integration Site ◽  
Low Cost ◽  
Safety Evaluation ◽  
Read Length ◽  
Chromosomal Dna ◽  
Wide Range

Abstract The gene and cell therapy fields are advancing rapidly, with a potential to treat and cure a wide range of diseases, and lentivirus-based gene transfer agents are the vector of choice for many investigators. Early cases of insertional mutagenesis caused by gammaretroviral vectors highlighted that integration site (IS) analysis was a major safety and quality control checkpoint for lentiviral applications. The methods established to detect lentiviral integrations using next-generation sequencing (NGS) are limited by short read length, inadvertent PCR bias, low yield, or lengthy protocols. Here, we describe a new method to sequence IS using Amplification-free Integration Site sequencing (AFIS-Seq). AFIS-Seq is based on amplification-free, Cas9-mediated enrichment of high-molecular-weight chromosomal DNA suitable for long-range Nanopore MinION sequencing. This accessible and low-cost approach generates long reads enabling IS mapping with high certainty within a single day. We demonstrate proof-of-concept by mapping IS of lentiviral vectors in a variety of cell models and report up to 1600-fold enrichment of the signal. This method can be further extended to sequencing of Cas9-mediated integration of genes and to in vivo analysis of IS. AFIS-Seq uses long-read sequencing to facilitate safety evaluation of preclinical lentiviral vector gene therapies by providing IS analysis with improved confidence.

Transitional Cell Hyperplasia and Carcinomas in Urinary Bladders of Transgenic Mice with Keratin 5 Promoter-Driven Cyclooxygenase-2 Overexpression

2005 ◽  
Vol 65 (5) ◽  
pp. 1808-1813 ◽  
Author(s):  
Russell D. Klein ◽  
Carolyn S. Van Pelt ◽  
Anita L. Sabichi ◽  
Jorge dela Cerda ◽  
Susan M. Fischer ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Transitional Cell ◽  
Cyclooxygenase 2 ◽  
Cell Hyperplasia ◽  
Keratin 5

scholarly journals Overexpression of antizyme in the hearts of transgenic mice prevents the isoprenaline-induced increase in cardiac ornithine decarboxylase activity and polyamines, but does not prevent cardiac hypertrophy

2000 ◽  
Vol 350 (3) ◽  
pp. 645-653 ◽  
Author(s):  
Caroline A. MACKINTOSH ◽  
David J. FEITH ◽  
Lisa M. SHANTZ ◽  
Anthony E. PEGG
Keyword(s):  
Transgenic Mice ◽  
Ornithine Decarboxylase ◽  
Prolonged Exposure ◽  
Constitutive Expression ◽  
Decarboxylase Activity ◽  
Cardiac Growth ◽  
Polyamine Content ◽  
Transgenic Lines ◽  
Response To Stress ◽  
Polyamine Uptake

Two lines of transgenic mice were produced with constitutive expression of antizyme-1 in the heart, driven from the cardiac α-myosin heavy chain promoter. The use of engineered antizyme cDNA in which nucleotide 205 had been deleted eliminated the need for polyamine-mediated frameshifting, normally necessary for translation of antizyme mRNA, and thus ensured the constitutive expression of antizyme. Antizyme-1 is thought to be a major factor in regulating cellular polyamine content, acting both to inhibit ornithine decarboxylase (ODC) activity and to target it for degradation, as well as preventing polyamine uptake. The two transgenic lines had substantial, but different, levels of antizyme in the heart, as detected by Western blotting and by the ability of heart extracts to inhibit exogenous purified ODC. Despite the high levels of antizyme, endogenous ODC activity was not completely abolished, with 10– 39% remaining, depending on the transgenic line. Additionally, a relatively small decrease (30–32%) in cardiac spermidine content was observed, with levels of putrescine and spermine unaffected. Interestingly, although the two lines of transgenic mice had different antizyme expression levels, they had almost identical cardiac polyamine content. When treated with a single acute dose of isoprenaline (isoproterenol), cardiac ODC activity and putrescine content were substantially increased (by 14-fold and 4.7-fold respectively) in non-transgenic littermate mice, but these increases were completely prevented in the transgenic mice from both founder lines. Prolonged exposure to isoprenaline also caused increases in cardiac ODC activity and polyamine content, as well as an increase in cardiac growth, in non-transgenic mice. Although the increases in cardiac ODC activity and polyamine content were prevented in the transgenic mice from both founder lines, the increase in cardiac growth was unaffected. These transgenic mice thus provide a valuable model system in which to study the importance of polyamine levels in cardiac growth and electrophysiology in response to stress.

The chicken skeletal muscle alpha-actin promoter is tissue specific in transgenic mice

1989 ◽  
Vol 9 (9) ◽  
pp. 3785-3792
Author(s):  
C J Petropoulos ◽  
M P Rosenberg ◽  
N A Jenkins ◽  
N G Copeland ◽  
S H Hughes
Keyword(s):  
Skeletal Muscle ◽  
Transgenic Mice ◽  
Striated Muscle ◽  
Transcriptional Start Site ◽  
Actin Gene ◽  
Tissue Specific ◽  
Adult Mice ◽  
Transgenic Lines ◽  
Alpha Actin ◽  
Chicken Skeletal Muscle

We have generated transgenic mouse lines that carry the promoter region of the chicken skeletal muscle alpha (alpha sk) actin gene linked to the bacterial chloramphenicol acetyltransferase (CAT) gene. In adult mice, the pattern of transgene expression resembled that of the endogenous alpha sk actin gene. In most of the transgenic lines, high levels of CAT activity were detected in striated muscle (skeletal and cardiac) but not in the other tissues tested. In striated muscle, transcription of the transgene was initiated at the normal transcriptional start site of the chicken alpha sk actin gene. The region from nucleotides -191 to +27 of the chicken alpha sk actin gene was sufficient to direct the expression of CAT in striated muscle of transgenic mice. These observations suggest that the mechanism of tissue-specific actin gene expression is well conserved in higher vertebrate species.

Transcriptional insulation of the human keratin 18 gene in transgenic mice

1993 ◽  
Vol 13 (4) ◽  
pp. 2214-2223
Author(s):  
N Neznanov ◽  
I S Thorey ◽  
G Ceceña ◽  
R G Oshima
Keyword(s):  
Transgenic Mice ◽  
Thymidine Kinase ◽  
Copy Number ◽  
Thymidine Kinase Gene ◽  
Flanking Sequence ◽  
Kinase Gene ◽  
Tissue Specific ◽  
Dependent Behavior ◽  
Flanking Sequences ◽  
Keratin 18

Expression of the 10-kb human keratin 18 (K18) gene in transgenic mice results in efficient and appropriate tissue-specific expression in a variety of internal epithelial organs, including liver, lung, intestine, kidney, and the ependymal epithelium of brain, but not in spleen, heart, or skeletal muscle. Expression at the RNA level is directly proportional to the number of integrated K18 transgenes. These results indicate that the K18 gene is able to insulate itself both from the commonly observed cis-acting effects of the sites of integration and from the potential complications of duplicated copies of the gene arranged in head-to-tail fashion. To begin to identify the K18 gene sequences responsible for this property of transcriptional insulation, additional transgenic mouse lines containing deletions of either the 5' or 3' distal end of the K18 gene have been characterized. Deletion of 1.5 kb of the distal 5' flanking sequence has no effect upon either the tissue specificity or the copy number-dependent behavior of the transgene. In contrast, deletion of the 3.5-kb 3' flanking sequence of the gene results in the loss of the copy number-dependent behavior of the gene in liver and intestine. However, expression in kidney, lung, and brain remains efficient and copy number dependent in these transgenic mice. Furthermore, herpes simplex virus thymidine kinase gene expression is copy number dependent in transgenic mice when the gene is located between the distal 5'- and 3'-flanking sequences of the K18 gene. Each adult transgenic male expressed the thymidine kinase gene in testes and brain and proportionally to the number of integrated transgenes. We conclude that the characteristic of copy number-dependent expression of the K18 gene is tissue specific because the sequence requirements for transcriptional insulation in adult liver and intestine are different from those for lung and kidney. In addition, the behavior of the transgenic thymidine kinase gene in testes and brain suggests that the property of transcriptional insulation of the K18 gene may be conferred by the distal flanking sequences of the K18 gene and, additionally, may function for other genes.

Sign in / Sign up

Export Citation Format

Share Document