scholarly journals Position-specific activity of the Hox1.1 promoter in transgenic mice

Development ◽  
1990 ◽  
Vol 108 (3) ◽  
pp. 435-442 ◽  
Author(s):  
A.W. Puschel ◽  
R. Balling ◽  
P. Gruss
Keyword(s):  
Transgenic Mice ◽  
Transgene Expression ◽  
Hox Genes ◽  
Specific Activity ◽  
Regulatory Element ◽  
Single Cells ◽  
Expression Patterns ◽  
Positional Information ◽  
Promoter Sequences ◽  
Second Period

During development, positional values have to be assigned to groups of cells. The murine Hox genes are a class of genes that are predicted to be involved at some stage in this process. During embryogenesis they are expressed in distinct overlapping region- and stage-specific patterns and therefore must be regulated in response to positional information. In this study, we have analysed the activity of Hox1.1 promoter sequences in transgenic mice. The use of lacZ as a marker allows a detailed analysis of expression at the single cell level during early embryonic development. We show that 3.6 kbp of promoter and 1.7 kbp of 3′ sequences provide sufficient regulatory information to express a transgene in a spatial and temporal manner indistinguishable from the endogenous Hox1.1 gene during the period of development when Hox1.1 expression is established. The activation occurs in a strict order in specific ectodermal and mesodermal domains. Within each of these domains the transgene is activated over a period of four hours apparently randomly in single cells. In a following second period, Hox1.1 and transgene expression patterns diverge. In this period, transgene expression persists in many mesodermally derived cells that do not express Hox1.1 indicating the absence of a negative regulatory element in the transgene. The anterior boundary of transgene expression is identical to that of Hox1.1. However, no posterior boundary of transgene expression is set, suggesting that a separate element absent from the transgene specifies this boundary.

Transducing positional information to the Hox genes: critical interaction of cdx gene products with position-sensitive regulatory elements

Development ◽  
1998 ◽  
Vol 125 (22) ◽  
pp. 4349-4358 ◽  
Author(s):  
J. Charite ◽  
W. de Graaff ◽  
D. Consten ◽  
M.J. Reijnen ◽  
J. Korving ◽  
...  
Keyword(s):  
Binding Sites ◽  
Hox Genes ◽  
Regulatory Element ◽  
Ectopic Expression ◽  
Positional Information ◽  
Regulatory Elements ◽  
Gene Products ◽  
Anteroposterior Patterning

Studies of pattern formation in the vertebrate central nervous system indicate that anteroposterior positional information is generated in the embryo by signalling gradients of an as yet unknown nature. We searched for transcription factors that transduce this information to the Hox genes. Based on the assumption that the activity levels of such factors might vary with position along the anteroposterior axis, we devised an in vivo assay to detect responsiveness of cis-acting sequences to such differentially active factors. We used this assay to analyze a Hoxb8 regulatory element, and detected the most pronounced response in a short stretch of DNA containing a cluster of potential CDX binding sites. We show that differentially expressed DNA binding proteins are present in gastrulating embryos that bind to these sites in vitro, that cdx gene products are among these, and that binding site mutations that abolish binding of these proteins completely destroy the ability of the regulatory element to drive regionally restricted expression in the embryo. Finally, we show that ectopic expression of cdx gene products anteriorizes expression of reporter transgenes driven by this regulatory element, as well as that of the endogenous Hoxb8 gene, in a manner that is consistent with them being essential transducers of positional information. These data suggest that, in contrast to Drosophila Caudal, vertebrate cdx gene products transduce positional information directly to the Hox genes, acting through CDX binding sites in their enhancers. This may represent the ancestral mode of action of caudal homologues, which are involved in anteroposterior patterning in organisms with widely divergent body plans and modes of development.

beta-MHC transgene expression in suspended and mechanically overloaded/suspended soleus muscle of transgenic mice

1997 ◽  
Vol 272 (5) ◽  
pp. R1552-R1561 ◽  
Author(s):  
J. J. McCarthy ◽  
A. M. Fox ◽  
G. L. Tsika ◽  
L. Gao ◽  
R. W. Tsika
Keyword(s):  
Transgenic Mice ◽  
Soleus Muscle ◽  
Transgene Expression ◽  
Specific Activity ◽  
Fiber Type ◽  
Weight Bearing ◽  
Troponin C ◽  
Hindlimb Suspension ◽  
Regulatory Sequences ◽  
Type I

Non-weight-bearing (NWB) activity [space flight and hindlimb suspension (HS)] results in the loss of soleus muscle mass, a slow-to-fast fiber-type conversion, and decreased beta-myosin heavy chain (beta-MHC) protein and mRNA expression. To identify beta-MHC promoter sequences required for decreased beta-MHC expression in response to HS, we have modified an existing noninvasive hindlimb unweighting model to accommodate the use of (transgenic) mice. After 2 wk of HS, body and muscle (soleus > gastrocnemius > plantaris) weights were decreased as was the proportion of histochemically classified type I fibers in HS soleus muscle. Northern blot analysis revealed decreases in endogenous mRNA representing beta-MHC, slow myosin light chain 1 and 2, and cardiac/slow troponin C, whereas those representing skeletal troponin C, muscle creatine kinase, and glyceraldehyde-3-phosphate dehydrogenase increased. Protein extracts prepared from HS soleus (SS) muscle of mice harboring transgenes comprised of 5.6 or 0.6 kilobase of wild type (wt) mouse beta-MHC promoter (beta 5.6 wt, beta 0.6wt) and those carrying the simultaneous mutation (mut) of the MCAT, C-rich, and beta e3 subregions (beta 5.6mut3, beta 0.6mut3) revealed decreases in chloramphenicol acetyltransferase (CAT) specific activity relative to respective controls. Decreased CAT mRNA was observed for transgene beta 5.6mut3, line 85. Two weeks of the simultaneous imposition of mechanical overload (synergist ablation) and HS (MOV/HS) countermanded the loss in absolute and normalized SS weight but did not decrease beta 0.6wt transgene expression. These transgenic results demonstrate that regulatory sequences within a 600-base pair beta-MHC promoter are sufficient to direct decreased transcription of beta-MHC transgenes after 2 wk of HS.

scholarly journals A transgenic pig model expressing a ZsGreen1 reporter across an extensive array of tissues

2018 ◽  
Author(s):  
Amy T. Desaulniers ◽  
Rebecca A. Cederberg ◽  
Elizabeth P. Carreiro ◽  
Channabasavaiah B. Gurumurthy ◽  
Brett R. White
Keyword(s):  
Transgene Expression ◽  
Specific Activity ◽  
Integration Site ◽  
Expression Patterns ◽  
Genetically Engineered ◽  
Cmv Promoter ◽  
Tissue Samples ◽  
Tissue Specific ◽  
Wide Range ◽  
Agricultural Industries

ABSTRACTBackgroundThe advent of genetically engineered pig production has revealed a wide array of opportunities to enhance both biomedical and agricultural industries. One powerful method to develop these models is transgenesis; however, selection of a suitable promoter to drive transgene expression is critical. The cytomegalovirus (CMV) promoter is the most commonly used viral promoter as it robustly drives transgene expression in a ubiquitous nature. However, recent reports suggest that the level of CMV promoter activity is tissue-dependent in the pig. Therefore, the objective of this study was to quantify the activity of the CMV promoter in a wide range of porcine tissues. Swine harboring a CMV-ZsGreen1 transgene with a single integration site were utilized for this study. Thirty five tissue samples were collected from neonatal hemizygous (n = 3) and homozygous (n = 3) transgenic piglets and analyzed for ZsGreen1 abundance via immunoblot.ResultsZsGreen1 was detected in all tissues examined; however, quantification revealed that ZsGreen1 protein levels were tissue-specific. Within organs of the digestive system, for example, ZsGreen1 was most abundant in the salivary gland, moderately produced in the esophagus and levels were lowest in the stomach. Interestingly, abundance of ZsGreen1 also differed within organ. For instance, levels were highest in the right ventricle compared with other chambers of the heart. There was no effect of transgene dose as ZsGreen1 expression patterns were similar between homozygous and hemizygous piglets.ConclusionsUltimately, these results elucidate the tissue-specific activity of the CMV promoter in the neonatal pig. Moreover, this model can serve as a useful tool for research applications requiring reporter gene activity in mammalian organs.

scholarly journals Separate elements cause lineage restriction and specify boundaries of Hox-1.1 expression

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 279-287 ◽  
Author(s):  
A.W. Puschel ◽  
R. Balling ◽  
P. Gruss
Keyword(s):  
Transgenic Mice ◽  
Hox Genes ◽  
Positional Information ◽  
Regulatory Elements ◽  
Specific Region ◽  
Regulatory Sequences ◽  
Anteroposterior Axis ◽  
Positional Identity ◽  
Developmental Programme ◽  
Responsive Element

The Hox genes are a class of putative developmental control genes that are thought to be involved in the specification of positional identity along the anteroposterior axis of the vertebrate embryo. It is apparent from their expression pattern that their regulation is dependent upon positional information. In a previous analysis of the Hox-1.1 promoter in transgenic mice, we identified sequences that were sufficient to establish transgene expression in a specific region of the embryo. The construct used, however, did not contain enough regulatory sequences to reproduce all aspects of Hox-1.1 expression. In particular, neither a posterior boundary nor a restriction of expression to prevertebrae was achieved. Here we show correct regulation by Hox-1.1 sequences in transgenic mice and identify the elements responsible for different levels of control. Concomitant with the subdivision of mesodermal cells into different lineages during gastrulation and organogenesis, Hox-1.1 expression is restricted to successively smaller sets of cells. Distinct elements are required at different stages of development to execute this developmental programme. One position-responsive element (130 bp nontranslated leader) was shown to be crucial for the restriction of expression not only along the anteroposterior axis of the embryo, setting the posterior border, but also along the dorsoventral axis of the neural tube and to the lineage giving rise to the prevertebrae. Thus, Hox-1.1 expression is established in a specific region of the embryo and in a specific lineage of the mesoderm by restricting the activity of the promoter by the combined effect of several regulatory elements.

scholarly journals Hox gene expression during the development of the phoronid Phoronopsis harmeri

2019 ◽  
Author(s):  
Ludwik Gąsiorowski ◽  
Andreas Hejnol
Keyword(s):  
Gene Expression ◽  
Larval Development ◽  
Hox Genes ◽  
Expression Patterns ◽  
Positional Information ◽  
Larval Body ◽  
Hox Gene ◽  
Larval Stages ◽  
Phoronopsis Harmeri ◽  
Embryonic And Larval Development

AbstractBackgroundPhoronida is a small group of marine worm-like suspension feeders, which together with brachiopods and bryozoans form the clade Lophophorata. Although their development is well studied on the morphological level, data regarding gene expression during this process are scarce and restricted to the analysis of relatively few transcription factors. Here we present a description of the expression patterns of Hox genes during the embryonic and larval development of the phoronid Phoronopsis harmeri.ResultsWe identified sequences of 8 Hox genes in the transcriptome of P. harmeri and determined their expression pattern during embryonic and larval development using whole mount in situ hybridization. We found that none of the Hox genes is expressed during embryonic development. Instead their expression is initiated in the later developmental stages, when the larval body is already formed. The Hox genes are expressed in the metasomal sac, posterior mesoderm and junction between midgut and hindgut - structures that represent rudiments of the adult worm, which emerges through the process of drastic metamorphosis. Additionally, two Hox genes are expressed in the posterior telotroch, which develops in the later larval stages.ConclusionsThe lack of Hox gene expression during early development of P. harmeri indicates that the larval body develops without positional information of the Hox patterning system. Such phenomenon might be a consequence of the evolutionary intercalation of the larval form into an ancestral, direct life cycle of phoronids. Accordingly, the specific actinotrocha larva found only in Phoronida, would represent an evolutionary novelty, for which an alternative molecular mechanism of antrerior-posterior patterning was recruited. Another explanation of the observed Hox gene expression is that the actinotrocha represents a “head larva”, which is composed of the most anterior body region that is devoid of Hox gene expression. This implies that the Hox patterning system is used for the positional information of the trunk rudiments and is, therefore, delayed to the later larval stages. Future investigation on head-specific genes expression is needed to test this hypothesis.

scholarly journals Molecular insights into the origin of the Hox-TALE patterning system

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Bruno Hudry ◽  
Morgane Thomas-Chollier ◽  
Yael Volovik ◽  
Marilyne Duffraisse ◽  
Amélie Dard ◽  
...  
Keyword(s):  
Hox Genes ◽  
Expression Patterns ◽  
Homeobox Gene ◽  
Gene Families ◽  
Positional Information ◽  
Related Protein ◽  
Hox Proteins ◽  
Body Form ◽  
Eukaryote Evolution ◽  
Anterior Posterior

Despite tremendous body form diversity in nature, bilaterian animals share common sets of developmental genes that display conserved expression patterns in the embryo. Among them are the Hox genes, which define different identities along the anterior–posterior axis. Hox proteins exert their function by interaction with TALE transcription factors. Hox and TALE members are also present in some but not all non-bilaterian phyla, raising the question of how Hox–TALE interactions evolved to provide positional information. By using proteins from unicellular and multicellular lineages, we showed that these networks emerged from an ancestral generic motif present in Hox and other related protein families. Interestingly, Hox-TALE networks experienced additional and extensive molecular innovations that were likely crucial for differentiating Hox functions along body plans. Together our results highlight how homeobox gene families evolved during eukaryote evolution to eventually constitute a major patterning system in Eumetazoans.

Dysregulation of HOX as a Potential Therapeutic Target in Breast Cancer

2020 ◽  
Vol 27 ◽  
Author(s):  
Ji-Yeon Lee ◽  
Myoung Hee Kim
Keyword(s):  
Breast Cancer ◽  
Hox Genes ◽  
Therapeutic Potential ◽  
Expression Patterns ◽  
Genome Structure ◽  
Control Cell ◽  
Three Dimensional ◽  
Cellular Processes ◽  
Hox Protein

: HOX genes belong to the highly conserved homeobox superfamily, responsible for the regulation of various cellular processes that control cell homeostasis, from embryogenesis to carcinogenesis. The abnormal expression of HOX genes is observed in various cancers, including breast cancer; they act as oncogenes or as suppressors of cancer, according to context. In this review, we analyze HOX gene expression patterns in breast cancer and examine their relationship, based on the three-dimensional genome structure of the HOX locus. The presence of non-coding RNAs, embedded within the HOX cluster, and the role of these molecules in breast cancer have been reviewed. We further evaluate the characteristic activity of HOX protein in breast cancer and its therapeutic potential.

scholarly journals The CD11b promoter directs high-level expression of reporter genes in macrophages in transgenic mice [published erratum appears in Blood 1995 Apr 1;85(7):1983]

Blood ◽  
1995 ◽  
Vol 85 (2) ◽  
pp. 319-329 ◽  
Author(s):  
S Dziennis ◽  
RA Van Etten ◽  
HL Pahl ◽  
DL Morris ◽  
TL Rothstein ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transgenic Mice ◽  
Transgene Expression ◽  
Heterologous Gene Expression ◽  
Myeloid Cells ◽  
Reporter Genes ◽  
Regulatory Elements ◽  
Specific Expression ◽  
High Level

Abstract CD11b is the alpha chain of the Mac-1 integrin and is preferentially expressed in myeloid cells (neutrophils, monocytes, and macrophages). We have previously shown that the CD11b promoter directs cell-type- specific expression in myeloid lines using transient transfection assays. To confirm that these promoter sequences contain the proper regulatory elements for correct myeloid expression of CD11b in vivo, we have used the -1.7-kb human CD11b promoter to direct reporter gene expression in transgenic mice. Stable founder lines were generated with two different reporter genes, a Thy 1.1 surface marker and the Escherichia coli lacZ (beta-galactosidase) gene. Analysis of founders generated with each reporter demonstrated that the CD11b promoter was capable of driving high levels of transgene expression in murine macrophages for the lifetime of the animals. Similar to the endogenous gene, transgene expression was preferentially found in mature monocytes, macrophages, and neutrophils and not in myeloid precursors. These experiments indicate that the -1.7 CD11b promoter contains the regulatory elements sufficient for high-level macrophage expression. This promoter should be useful for targeting heterologous gene expression to mature myeloid cells.

Interactions of insulin-like growth factor (IGF)-II and growth hormone in vivo: circulating levels of IGF-I and IGF-binding proteins in transgenic mice

1997 ◽  
pp. 701-708 ◽  
Author(s):  
A Blackburn ◽  
RA Dressendorfer ◽  
WF Blum ◽  
M Erhard ◽  
G Brem ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Transgene Expression ◽  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Standard Diet ◽  
Igf I ◽  
Igf Binding ◽  
B Mice

To study interactions between insulin-like growth factor-II (IGF-II) and growth hormone (GH) in vivo, we crossed hemizygous transgenic mice carrying phosphoenolpyruvate carboxykinase (PEPCK)-IGF-II fusion genes with hemizygous PEPCK-bovine GH (bGH) transgenic mice. Offspring harbouring both transgenes (IB), the IGF-II transgene (I) or the bGH transgene (B), and non-transgenic littermates (C) were obtained. Blood samples were taken before (end of week 12) and after (end of week 14) the mice had received a diet high in protein and low in carbohydrates to stimulate PEPCK promoter-controlled transgene expression. Mean serum GH concentrations of both B and IB mice corresponded to 900 ng/ml and increased more than twofold (P < 0.001) after 1 week of the high-protein diet. GH concentrations in controls and I mice were less than 20 ng/ml. Serum IGF-II concentrations in I and IB mice were three-to fourfold higher than those in C and B mice. Whereas IGF-II concentrations were not changed by the high-protein diet in the last two groups, serum IGF-II increased significantly in I (P < 0.001) and IB mice (P < 0.05). This increase was significantly (P < 0.05) less pronounced in IB than in C and I mice. Circulating IGF-I concentrations were about twofold (P < 0.001) higher in B and IB than in C and I mice, and showed a tendency to be lower in I than in C and in IB than in B mice when animals were maintained on the standard diet. The high-protein diet did not change circulating IGF-I concentrations in controls and B mice, but resulted in a significant reduction of serum IGF-I concentrations in I (P < 0.05) and IB mice (P < 0.001). Consequently, after PEPCK-IGF-II transgene expression was stimulated, serum IGF-I concentrations were significantly (P < 0.05) lower in I than in C and in IB than in B mice. Serum IGF-binding protein (IGFBP)-2 concentrations were significantly (P < 0.05) higher in I mice than in all other groups when mice were maintained on the standard diet, with a tendency to reduced IGFBP-2 concentrations in B mice. After the high-protein diet, serum IGFBP-2 concentrations did not change in C and I mice, but increased by two- to threefold in B and IB mice (P < 0.001). Serum IGFBP-3 concentrations tended to be greater in B and IB than in C and I mice, but these differences were mostly not significant. IGFBP-4 concentrations were significantly (P < 0.001) increased by GH overproduction in B and IB mice. Our data suggest that the reduction in circulating IGF-I concentrations by increased IGF-II is most probably due to the limited serum IGF binding capacity and the short half-life of free IGFs, rather than to a reduction in GH-dependent IGF-I production. Effects of GH overproduction on serum IGFBP-2 concentrations depend on dietary factors and may be both inhibitory and stimulatory.

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