Cardiomyocyte proliferation in mice expressing alpha-cardiac myosin heavy chain-SV40 T-antigen transgenes

1992 ◽  
Vol 262 (6) ◽  
pp. H1867-H1876 ◽  
Author(s):  
E. B. Katz ◽  
M. E. Steinhelper ◽  
J. B. Delcarpio ◽  
A. I. Daud ◽  
W. C. Claycomb ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Antigen Expression ◽  
T Antigen ◽  
Proliferative Potential ◽  
Cardiac Myosin ◽  
Large T Antigen ◽  
Sv40 Large T Antigen ◽  
Ventricular Cardiomyocytes

To determine the proliferative potential of adult ventricular cardiomyocytes, we have generated transgenic mice that express the SV40 large T-antigen oncogene in the heart. A fusion gene comprised of the rat alpha-cardiac myosin heavy chain promoter and the SV40 early region was used to target oncogene expression to the myocardium. Expression of SV40 large T-antigen was observed in both atrial and ventricular cardiomyocytes in adult transgenic animals. T-antigen expression was associated with hyperplasia in the targeted cells. Immunohistological analysis indicated that the proliferating cells continued to express sarcomeric myosin. Electron microscopic examination demonstrated that cardiomyocytes in various stages of the cell cycle retained ultrastructural characteristics typical of mitotic cardiac muscle cells in vivo. Cardiomyocytes isolated from transgenic tumors were able to proliferate in culture and retained a differentiated phenotype, as evidenced by spontaneous contractile activity. Preliminary studies indicate that these cells can undergo a limited number of passages while retaining this differentiated phenotype. These studies demonstrate that both ventricular and atrial cardiomyocytes from transgenic mice proliferate in response to targeted T-antigen expression.

Morphometry and muscle gene expression in hypertrophied hearts from polyomavirus large T antigen transgenic mice

1995 ◽  
Vol 269 (1) ◽  
pp. H86-H95 ◽  
Author(s):  
E. Holder ◽  
B. Mitmaker ◽  
L. Alpert ◽  
L. Chalifour
Keyword(s):  
Transgenic Mice ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Troponin I ◽  
T Antigen ◽  
Large T Antigen ◽  
Cross Sectional

Transgenic mice expressing polyomavirus large T antigen (PVLT) in cardiomyocytes develop a cardiac hypertrophy in adulthood. Morphometric analysis identified cardiomyocytes enlarged up to ninefold in cross-sectional area in the adult transgenic hearts compared with normal age-matched nontransgenic hearts. Most enlarged cardiomyocytes were found in the subendocardium, whereas normal-sized cardiomyocytes were localized to the midmyocardium. Transgenic hearts did not express detectable skeletal muscle actin mRNA or protein, or skeletal troponin I isoform mRNA. Some, but not all, transgenic hearts expressed an increase in the beta-myosin heavy chain mRNA. All five transgenic mice tested had increased expression of atrial natriuretic factor (ANF) mRNA. Whereas normal hearts expressed three myosin light chain proteins of 19, 16, and 15 kDa, we found that the 19-kDa myosin light chain was not observed in the transgenic hearts. We conclude that adult, PVLT-expressing, transgenic mice developed enlarged cardiomyocytes with an increase in beta-myosin heavy chain and ANF mRNA expression, but a widespread skeletal isoform usage was not present in these transgenic mice. The adult transgenic hearts thus display histological and molecular changes similar to those found in hypertrophy induced by a pressure overload in vivo.

SV40 Large T Antigen Interferes with Adult Myosin Heavy Chain Expression, but Not with Differentiation of Human Satellite Cells

1996 ◽  
Vol 225 (2) ◽  
pp. 268-276 ◽  
Author(s):  
V. Mouly ◽  
F. Edom ◽  
S. Decary ◽  
P. Vicart ◽  
J.P. Barbet ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Satellite Cells ◽  
Heavy Chain ◽  
T Antigen ◽  
Large T Antigen ◽  
Sv40 Large T Antigen

scholarly journals Developmental regulation of lck gene expression in T lymphocytes.

1991 ◽  
Vol 173 (2) ◽  
pp. 383-393 ◽  
Author(s):  
R S Wildin ◽  
A M Garvin ◽  
S Pawar ◽  
D B Lewis ◽  
K M Abraham ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Short Interval ◽  
T Antigen ◽  
Lymphoid Cells ◽  
Proximal Promoter ◽  
Large T Antigen ◽  
Sv40 Large T Antigen ◽  
Promoter Sequences ◽  
Antigen Gene ◽  
Distal Promoter

In the mouse and human, mRNA transcripts encoding the lymphocyte-specific protein tyrosine kinase p56lck are derived from two separate promoters resulting in heterogeneity in the 5' untranslated region sequence. The proximal promoter lies just 5' to the coding region for the gene and is active only in thymocytes. In contrast, the distal promoter lies 34 kilobases (kb) 5' in the human, and is active both in thymocytes and mature peripheral T cells. As previously reported, transgenic mice bearing functional proximal promoter sequence juxtaposed with the SV40 large T antigen gene invariably develop lymphoid tumors confined to the thymus. In the current work, transgenic mice bearing a 2.6-kb fragment of the human distal promoter fused to the SV40 large T antigen gene express large T antigen in thymocytes and in peripheral lymphoid cells, and develop tumors of both the thymus and the peripheral lymphoid organs. The ability of the human distal promoter to function appropriately in transgenic mice is consistent with the strong similarity observed between the mouse and human distal promoter sequences. With the exception of a single short interval that serves as a target for binding of nuclear factors, significant sequence similarity is not seen when the distal and proximal promoter sequences are compared. Hence, developmentally regulated, lineage-specific transcription of the lck gene is mediated by distinct promoter sequences that appear to be capable of functioning independently.

scholarly journals A pilot study of alternative TrkAIII splicing in Merkel cell carcinoma: a potential oncogenic mechanism and novel therapeutic target

2019 ◽  
Vol 38 (1) ◽  
Author(s):  
Lucia Cappabianca ◽  
Stefano Guadagni ◽  
Rita Maccarone ◽  
Michela Sebastiano ◽  
Alessandro Chiominto ◽  
...  
Keyword(s):  
Pilot Study ◽  
Therapeutic Target ◽  
Normal Skin ◽  
Stage Iv ◽  
Antigen Expression ◽  
T Antigen ◽  
Activation Mechanism ◽  
Merkel Cell ◽  
Large T Antigen ◽  
Sv40 Large T Antigen

Abstract Background Merkel cell carcinomas (MCCs) are rare, aggressive, therapeutically-challenging skin tumours that are increasing in incidence and have poor survival rates. The majority are caused by genomic Merkel cell polyomavirus (MCPyV) integration and MCPyV T-antigen expression. Recently, a potential oncogenic role for the tropomyosin-related tyrosine kinase A receptor (TrkA) has been proposed in MCC. Alternative TrkAIII splicing is a TrkA oncogenic activation mechanism that can be promoted by SV40 large T-antigen, an analogue of MCPyV large T-antigen. In this pilot study, therefore, we have evaluated TrkAIII splicing as a novel potential oncogenic mechanism and therapeutic target in MCPyV positive MCC. Methods Formalin-fixed paraffin-embedded MCC tissues, consisting of 10 stage IV, 1 stage IIIB, 1 stage IIB, 4 stage IIA and 2 stage I tumours, from patients diagnosed and treated from September 2006 to March, 2019, at the University of L’Aquila, L’Aquila, Italy, were compared to 3 primary basal cell carcinomas (BCCs), 3 primary squamous cell carcinomas (SCCs) and 2 normal skin samples by RT-PCR for MCPyV large T-antigen, small T-antigen, VP-1 expression and alternative TrkAIII splicing and by indirect IF for evidence of intracellular TrkA isoform expression and activation. Results 9 of 10 Recurrent stage IV MCCs were from patients (P.1–3) treated with surgery plus loco-regional Melphalan chemotherapy and remaining MMCs, including 1 stage IV tumour, were from patients treated with surgery alone (P. 4–11). All MCPyV positive MCCs exhibiting MCPyV large T-antigen expression (17 of 18MCCs, 90%) exhibited alternative TrkAIII mRNA splicing (100%), which was exclusive in a significant number and predominant (> 50%) in all stage IV MCCs and the majority of stage 1-III MCCs. MCCs with higher TrkAIII to 18S rRNA expression ratios also exhibited strong or intermediate immunoreactivity to anti-TrkA antibodies, consistent with cytoplasmic TrkAIII expression and activation. In contrast, the MCPyV negative MCC, BCCs, SCCs and normal skin tissues all exhibited exclusive fully-spliced TrkA mRNA expression, associated with variable immunoreactivity for non-phosphorylated but not phosphorylated TrkA. Conclusions MCPyV positive MCCs but not MCPyV negative MCC, BCCs and SCCs exhibit predominant alternative TrkAIII splicing, with evidence of intracellular TrkAIII activation. This establishes a new potential MCC subset, unveils a novel potential MCPyV oncogenic mechanism and identifies TrkAIII as a novel potential therapeutic target in MCPyV positive MCC.

Extended lifespan of normal human B lymphocytes experimentally infected by SV40 or transfected by SV40 large T antigen expression vector

2013 ◽  
Vol 37 (6) ◽  
pp. 681-689 ◽  
Author(s):  
Franca Nneka Alaribe ◽  
Elisa Mazzoni ◽  
Gian Matteo Rigolin ◽  
Lara Rizzotto ◽  
Stefania Maniero ◽  
...  
Keyword(s):  
B Lymphocytes ◽  
Expression Vector ◽  
Antigen Expression ◽  
T Antigen ◽  
Large T Antigen ◽  
Sv40 Large T Antigen ◽  
Extended Lifespan ◽  
Normal Human
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