Expression of Tropomyosin 2 Gene Isoforms in Human Cardiac Tissue

Dube, Syamalima; Yalamanchili, Santhi; Lachant, Joseph; Abbott, Lynn; Benz, Patricia; Dube, Dipak K.; Bj, Poiesz

doi:10.19070/2470-4563-140003

Cited by 2 publications

(3 citation statements)

References 23 publications

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“…The cell extraction buffer was supplemented with 1 mM PMSF and protease inhibitor cocktail (Roche Diagnostics Corporation, Indianapolis, IN, USA) following manufacturer specifications. The pellets were discarded and 10 µ l of supernatant from each sample was used for subsequent western blot analyses following our published protocol ( 17 ). Primary antibodies included TM311 (Sigma-Aldrich), TPM1E2a, CH1 anti-sarcomeric tropomyosin (Hybridoma Bank, DHSB, University of Iowa, IA, USA), and TPM2b 187–206 (kind gift of G.L.…”

Section: Methodsmentioning

confidence: 99%

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Expression of tropomyosin 2 gene isoforms in human breast cancer cell lines

et al. 2016

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In humans, four tropomyosin genes (TPM1, TPM2, TPM3, and TPM4) are known to produce a multitude of isoforms via alternate splicing and/or using alternate promoters. Expression of tropomyosin has been shown to be modulated at both the transcription and the translational levels. Tropomyosins are known to make up some of the stress fibers of human epithelial cells and differences in their expression has been demonstrated in malignant breast epithelial cell lines compared to 'normal' breast cell lines. We have recently reported the expression of four novel TPM1 isoforms (TPM1λ, TPM1µ, TPM1ν, and TPM1ξ) from human malignant tumor breast cell lines that are not expressed in adult and fetal cardiac tissue. Also, we evaluated their expression in relation to the stress fiber formation. In this study, nine malignant breast epithelial cell lines and three 'normal' breast cell lines were examined for stress fiber formation and expression of tropomyosin 2 (TPM2) isoform-specific RNAs and proteins. Stress fiber formation was assessed by immunofluorescence using Leica AF6000 Deconvolution microscope. Stress fiber formation was strong (++++) in the 'normal' cell lines and varied among the malignant cell lines (negative to +++). No new TPM2 gene RNA isoforms were identified, and TPM2β was the most frequently expressed TPM2 RNA and protein isoform. Stress fiber formation positively correlated with TPM2β RNA or protein expression at high, statistically significant degrees. Previously, we had shown that TPM1δ and TPM1λ positively and inversely, respectively, correlated with stress fiber formation. The most powerful predictor of stress fiber formation was the combination of TPM2β RNA, TPM1δ RNA, and the inverse of TPM1λ RNA expression. Our results suggest that the increased expression of TPM1λ and the decreased expression of TPM1δ RNA and TPM2β may lead to decreased stress fiber formation and malignant transformation in human breast epithelial cells.

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Section: Methodsmentioning

confidence: 99%

“…Also, the expression of TPM1δ, but not TPM1γ, was positively correlated with stress fiber formation. We have also published on the expression of novel TPM2 gene isoforms (TPM2δ-η) in human cardiac tissues ( 17 ). Given the above observations, we decided to re-examine TPM2 isoform expression in human breast cancer cell lines.…”

Section: Introductionmentioning

confidence: 99%

Expression of tropomyosin 2 gene isoforms in human breast cancer cell lines

et al. 2016

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“…The cell extraction buffer was supplemented with 1 mM PMSF and protease inhibitor cocktail (Roche Diagnostics Corporation, Indianapolis, IN) following manufacturer specifications. The pellets were discarded and 10 μ L of supernatant from each sample was used for subsequent western blot analyses following our published protocol [ 26 ]. Primary antibodies included TM311 (Sigma-Aldrich, St. Louis, MO), anti-TPM1k [ 12 ], and CH1 anti-sarcomeric tropomyosin (Hybridoma Bank, DHSB, University of Iowa, Iowa).…”

Section: Rna and Protein Analysesmentioning

confidence: 99%

Expression of Tropomyosin 1 Gene Isoforms in Human Breast Cancer Cell Lines

Dube

Yalamanchili

Lachant

et al. 2015

International Journal of Breast Cancer

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Nine malignant breast epithelial cell lines and 3 normal breast cell lines were examined for stress fiber formation and expression of TPM1 isoform-specific RNAs and proteins. Stress fiber formation was strong (++++) in the normal cell lines and varied among the malignant cell lines (negative to +++). Although TPM1γ and TPM1δ were the dominant transcripts of TPM1, there was no clear evidence for TPM1δ protein expression. Four novel human TPM1 gene RNA isoforms were discovered (λ, μ, ν, and ξ), which were not identified in adult and fetal human cardiac tissues. TPM1λ was the most frequent isoform expressed in the malignant breast cell lines, and it was absent in normal breast epithelial cell lines. By western blotting, we were unable to distinguish between TPM1γ, λ, and ν protein expression, which were the only TPM1 gene protein isoforms potentially expressed. Some malignant cell lines demonstrated increased or decreased expression of these isoforms relative to the normal breast cell lines. Stress fiber formation did not correlate with TPM1γ RNA expression but significantly and inversely correlated with TPM1δ and TPM1λ expression, respectively. The exact differences in expression of these novel isoforms and their functional properties in breast epithelial cells will require further study.

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Expression of Tropomyosin 2 Gene Isoforms in Human Cardiac Tissue

Cited by 2 publications

References 23 publications

Expression of tropomyosin 2 gene isoforms in human breast cancer cell lines

Expression of tropomyosin 2 gene isoforms in human breast cancer cell lines

Expression of Tropomyosin 1 Gene Isoforms in Human Breast Cancer Cell Lines

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