Position-dependent variegation of a CD4 minigene specifically expressed in mature CD4+ T cells

Boyer, Olivier; Zhao, Jichen; Cohen, Jacques; Onclercq, Rosine; Depetris, Danielle; Mattéi, M. G.; Klatzmann, David

doi:10.1016/s0165-2478(97)85299-6

Cited by 8 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result is in agreement with data from other groups who used similar human 14,15 or mouse 10 constructs. In contrast, other Tg mice harboring apparently similar mCD4 16,17 or hCD4 18,19 constructs did not express their reporter gene in the CD4 ϩ CD8 ϩ DP T cells, while retaining expression in the SP CD4 ϩ T cells. These discrepancies may reflect the presence or not of intronic element(s), just in front of exon 2, required for the expression in DP T cells and identified by Rushton and colleagues 20 as the proximal promoter.…”

Section: Resultsmentioning

confidence: 84%

Distinct regulatory elements are required for faithful expression of human CD4 in T cells, macrophages, and dendritic cells of transgenic mice

Hanna

Rebaï

Poudrier

et al. 2001

Blood

View full text Add to dashboard Cite

To identify the regulatory elements controlling expression of the human CD4 (hCD4) gene in different cell types of the immune system, deletion and chimeric (human/murine) reporter genes were constructed and tested in transgenic (Tg) mice. Regulatory elements required for the proper hCD4 expression in the immature double-positive thymic T cells were identified in the enhancer and in the 3 end of intron 1. Expression of hCD4 in macrophages is controlled by at least 2 sets of regulatory elements: one present in front of exon 1 and the second at the 5 end of intron 1. The hCD4 elements required for expression on both myeloid and lymphoid CD8␣ ؉ dendritic cells (DCs) from lymph node and thymus were found IntroductionThe CD4 cell surface receptor is expressed on many mouse or human cell populations, namely, on very early T-cell precursors (CD4 Low CD44 ϩ CD25 Ϫ ), on immature double-positive (DP) CD4 ϩ CD8 ϩ T cells, on mature single-positive (SP) CD4 ϩ CD8 Ϫ T cells, 1,2 and on a subpopulation of CD8␣ Ϫ dendritic cells (DCs). 3,4 In humans, CD4 is also expressed in monocytes, macrophages, microglial cells, and some DCs. 5,6 Several regulatory elements of the murine and human CD4 genes (mCD4, hCD4) have been identified and tested in transgenic (Tg) animal studies (reviewed by Ellmeier et al 1 and Killeen and Littman 2 ). We have exploited the structural homology, but the different patterns of expression, of the mCD4 and hCD4 genes and made chimeric mCD4/hCD4 transgenes, to map more precisely the regulatory regions of the hCD4 gene controlling its expression in macrophages and in DCs. Study design Tg miceConstructs CD4A, CD4B, and CD4C were described previously. 7 Other constructs were generated from the CD4C DNA by replacing the 2.6-kilobase pair (kbp) SacI fragment with the mouse promoter (CD4E), or the 9-kbp EcoRV-XbaI fragment with the murine silencer (0.5 kbp) (CD4F), or by deleting the 6-kbp EcoRV fragment (CD4H). Tg mice were generated as described elsewhere. 7 Flow cytometryCell suspensions were prepared from lymphoid organs and stained with antibodies, as previously described. 7 Peritoneal macrophages were plated overnight. Between 80% and 95% of them stained positive for Mac-1 ( Figure 2B), Mac3, and F4/80 (data not shown). DCs were isolated from lymph node (LN) 8 and thymus. 9 Results and discussionThe Tg mice harboring 6 different DNAs were generated ( Figure 1). Northern blot analysis revealed that expression was highest in the thymus but was also detectable in the spleen and LNs, and was negative in all other organs tested (liver, heart, kidney, lung, intestine, muscle, brain; data not shown). This result is consistent with previous studies indicating that the human and mouse CD4 promoter/enhancer alone or in combination is sufficient to restrict expression to hematopoietic tissues. 7,10-13 As expected, the level of expression varied among different founders carrying the same construct, an effect most likely related to the site of integration of the inoculated DNA.Expression of hCD4 in DP CD4 ؉ CD8 ؉ T ...

show abstract

Section: Resultsmentioning

confidence: 84%

Distinct regulatory elements are required for faithful expression of human CD4 in T cells, macrophages, and dendritic cells of transgenic mice

Hanna

Rebaï

Poudrier

et al. 2001

Blood

View full text Add to dashboard Cite

show abstract

“…A fourth significant observation was that the percentage of NK cells expressing the transgene was quite similar in all six of the lines that exhibited variegation, and averaged close to the percentage of NK cells in B6 mice that express the endogenous Ly49A B6 gene. In contrast, PEV of transgenes results in substantial variation in the percentages of expressing cells in different transgenic lines (35,36). Finally, the fraction of cells expressing the transgene was regulated much like that of the endogenous gene.…”

Section: Variegation Of Transgene Expressionmentioning

confidence: 98%

Genomic Ly49A Transgenes: Basis of Variegated Ly49A Gene Expression and Identification of a Critical Regulatory Element

Tanamachi

Moniot

Cado

et al. 2004

The Journal of Immunology

View full text Add to dashboard Cite

Several gene families are known in which member genes are expressed in variegated patterns in differentiated cell types. Mechanisms responsible for imposition of a variegated pattern of gene expression are unknown. Members of the closely linked Ly49 inhibitory receptor gene family are expressed in a variegated fashion by NK cells. Variegated expression of these genes results in subsets of NK cells that differ in specificity for MHC class I molecules. To address the mechanisms underlying variegation, a 30-kb genomic fragment containing a single Ly49 gene was used to generate a panel of murine transgenic lines. The results demonstrated that, in almost all of the lines, the isolated Ly49A gene was expressed in a variegated pattern, remarkably similar in nearly all respects to the expression pattern of the endogenous Ly49A gene. Furthermore, the developmental timing of gene expression and regulation by host MHC molecules closely mirrored that of the endogenous Ly49A gene. Therefore, Ly49 variegation does not require competition in cis between different Ly49 genes, and the sequences imposing variegation are located proximally to Ly49 genes. Efforts to define regulatory elements of the Ly49A gene led to the identification of a DNase I hypersensitive site 4.5 kb upstream of the Ly49A gene transcription initiation site, which was shown to be essential for transgene expression. Highly related sequence elements were found upstream of other Ly49 genes, suggesting that a similar regulatory element controls each Ly49 gene.

show abstract

“…Furthermore, it appears that the decision on whether to express a hCD2 transgene with a disabled LCR is a stochastic one, and once made, it is maintained through subsequent cell divisions (4). Very similar observations were made in experiments involving other disabled LCRs (3,(7)(8)(9).…”

mentioning

confidence: 61%

Human High Mobility Group Box Transcription Factor 1 Affects Thymocyte Development and Transgene Variegation

Sekkali¹,

Szabat²,

Ktistaki³

et al. 2005

The Journal of Immunology

View full text Add to dashboard Cite

It has been shown previously that a human CD2 (hCD2) disabled locus control region (LCR) transgene is unable to establish an open chromatin configuration in all the T cells, and this leads to position effect variegation of the transgene. In this study we show that thymus-specific overexpression of human high mobility group box transcription factor 1 (HBP1), a transcription factor that binds a specific sequence within the hCD2 LCR, affects thymus cellularity as well as the number of CD8+ thymocytes in two independent transgenic mouse lines and increases the proportion of T cells that fully activate the transgenic locus in hCD2 variegating mice in a sequence-specific dependent manner. This finding suggests that overexpression of HBP1 can affect lineage commitment and can relieve the suppressive influence of heterochromatin, allowing thymocytes to express the variegating target locus more efficiently. These effects could be the result of direct HBP1 action on LCR activity. Alternatively, the extra HBP1 molecules may sequester repressive elements away from the LCR, thus allowing transcription permissive states to form on the transgene locus.

show abstract

Position-dependent variegation of a CD4 minigene specifically expressed in mature CD4+ T cells

Cited by 8 publications

References 0 publications

Distinct regulatory elements are required for faithful expression of human CD4 in T cells, macrophages, and dendritic cells of transgenic mice

Distinct regulatory elements are required for faithful expression of human CD4 in T cells, macrophages, and dendritic cells of transgenic mice

Genomic Ly49A Transgenes: Basis of Variegated Ly49A Gene Expression and Identification of a Critical Regulatory Element

Human High Mobility Group Box Transcription Factor 1 Affects Thymocyte Development and Transgene Variegation

Contact Info

Product

Resources

About