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3.
Sci Rep ; 10(1): 13125, 2020 08 04.
Article En | MEDLINE | ID: mdl-32753634

Regulated expression of genetic elements that either encode polypeptides or various types of functional RNA is a fundamental goal for gene therapy. Inducible expression may be preferred over constitutive promoters to allow clinician-based control of gene expression. Existing Tet-On systems represent one of the tightest rheostats for control of gene expression in mammals. However, basal expression in absence of tetracycline compromises the widespread application of Tet-controlled systems in gene therapy. We demonstrate that the order of P2A-linked genes of interest was critical for maximal response and tightness of a chimeric antigen receptor (CAR)-based construct. The introduction of G72V mutation in the activation region of the TetR component of the rtTA further improved the fold response. Although the G72V mutation resulted in a removal of a cryptic splice site within rtTA, additional removal of this splice site led to only a modest improvement in the fold-response. Selective removal of key promoter elements (namely the BRE, TATA box, DPE and the four predicted Inr) confirmed the suitability of the minimal CMV promoter and its downstream sequences for supporting inducible expression. The results demonstrate marked improvement of the rtTA based Tet-On system in Sleeping Beauty for applications such as CAR T cell therapy.


DNA Transposable Elements/genetics , Receptors, Chimeric Antigen/genetics , Tetracycline/pharmacology , Amino Acid Sequence , HEK293 Cells , Humans , Models, Molecular , Mutation , Protein Conformation , Receptors, Chimeric Antigen/chemistry , Response Elements/drug effects
4.
Gene ; 762: 145016, 2020 Dec 15.
Article En | MEDLINE | ID: mdl-32777522

Mcl-1 is a member of the Bcl-2 anti-apoptotic protein family with important roles in the development, lifespan and metabolism of lymphocytes, as well as oncogenesis. Mcl-1 displays the shortest half-life of all Bcl-2 family members, with miRNA interference and proteasomal degradation being major pathways for Mcl-1 downregulation. In this study, we have identified a previously undescribed control mechanism active at the RNA level. A divergently transcribed lncRNA LOC107985203 (named here mcl1-AS1) negatively modulated Mcl-1 expression resulting in downregulation of Mcl-1 at both mRNA and protein level in a time-dependent manner. Using reporter assays, we confirmed that the mcl1-AS1 lncRNA promoter was located within Mcl-1 coding region. We next placed mcl1-AS1 under tetracycline-inducible control and demonstrated decreased viability in HEK293 cells upon doxycycline induction. Inhibition of mcl1-AS1 with shRNA reversed drug sensitivity. Bioinformatics surveys predicted direct mcl1-AS1 lncRNA binding to Mcl-1 transcripts, suggesting its mechanism in Mcl-1 expression is at the transcriptional level, consistent with a common role for anti-sense transcripts. The identification of a bi-directional promoter and lncRNA controlling Mcl-1 expression will have implications for controlling Mcl-1 activity in cancer cells, or for the purpose of enhancing the lifespan and quality of anti-cancer T lymphocytes.


Myeloid Cell Leukemia Sequence 1 Protein/genetics , RNA, Antisense/genetics , RNA, Long Noncoding/genetics , Exons , HEK293 Cells , Humans , Introns , Myeloid Cell Leukemia Sequence 1 Protein/metabolism , Promoter Regions, Genetic , RNA, Antisense/metabolism , RNA, Long Noncoding/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism
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