Noboru Watanabe

BTEB2, a Krüppel-Like Transcription Factor, Regulates Expression of the SMemb/Nonmuscle Myosin Heavy Chain B (SMemb/NMHC-B) Gene

We have recently characterized the promoter region of the rabbit embryonic smooth muscle myosin heavy chain (SMemb/NMHC-B) gene and identified the 15-bp sequence, designated SE1, located at -105 from the transcriptional start site as an important regulatory element for its transcriptional activity in a smooth muscle cell (SMC) line. In this study, we attempted to isolate cDNA clones encoding for the transcription factors that control the expression of the SMemb gene through binding to this cis-regulatory element. We screened a lambdagt11 cDNA library prepared from C2/2 cells, a rabbit-derived SMC line, by using a radiolabeled concatenated oligonucleotide containing SE1 as a probe. Sequence analysis revealed that one of the cDNA clones corresponds to the rabbit homologue of basic transcriptional element binding protein-2 (BTEB2), which has previously been identified as one of the Krüppel-like transcription factor. Gel mobility shift assays and antibody supershift analyses with nuclear extracts from C2/2 cells indicate that BTEB2 is a major component of nuclear factor:SE1 complexes. Furthermore, a glutathione S-transferase-BTEB2 fusion protein binds to the SE1 in a sequence-specific manner. In support of the functionality of BTEB2 binding, basal promoter activity and BTEB2-induced transcriptional activation were markedly attenuated by the disruption of the SE1. In adult rabbit tissues, BTEB2 mRNA was most highly expressed in intestine, urinary bladder, and uterus. BTEB2 mRNA levels were downregulated in rabbit aorta during normal development. Moreover, immunohistochemical analysis indicated a marked induction of BTEB2 protein in the neointimal SMC after balloon injury in rat aorta. These results suggest that BTEB2 mediates the transcriptional regulation of the SMemb/NMHC-B gene and possibly plays a role in regulating gene expression during phenotypic modulation of vascular SMC.

Regulated expression of the BTEB2 transcription factor in vascular smooth muscle cells: analysis of developmental and pathological expression profiles shows implications as a predictive factor for restenosis.

BackgroundWe have previously shown BTEB2, a Krüppel-like zinc finger transcription factor, to regulate expression of the SMemb/NMHC-B gene, which has been implicated in phenotypic modulation of smooth muscle cells (SMCs). The present study was done to assess the developmental and pathological expression profiles of BTEB2 and to further evaluate the clinical relevance of BTEB2 expression in human coronary artery disease. Methods and ResultsImmunohistochemistry showed developmentally regulated expression of BTEB2 with abundant expression in fetal but not in adult aortic SMCs of humans and rabbits. In balloon-injured aortas, predominant expression of BTEB2 was seen in neointimal SMCs. Atherectomy specimens obtained from primary and restenotic lesions showed predominant expression of BTEB2 to stellate SMCs. The incidence of restenosis in primary lesions was significantly higher in lesions containing BTEB2-positive cells than in lesions without (55.6% versus 25.0%, P =0.01). ConclusionsThe present study shows that BTEB2 expression is developmentally and pathologically regulated. BTEB2 is preferentially expressed in dedifferentiated or activated SMCs. Examination of human coronary artery specimens suggests that primary lesions containing BTEB2-positive cells are associated with higher risk of restenosis than BTEB2-negative lesions. These results suggest that BTEB2 can serve as a molecular marker for phenotypic modulation of vascular SMCs.

Preferential Differentiation of P19 Mouse Embryonal Carcinoma Cells Into Smooth Muscle Cells Use of Retinoic Acid and Antisense Against the Central Nervous System–Specific POU Transcription Factor Brn-2

Investigation of the molecular mechanisms that control smooth muscle cell (SMC) development and differentiation is a prerequisite in understanding the regulatory mechanisms of physiological and pathological SMC-associated vascular processes. The pluripotent murine embryonal carcinoma P19 cell, whose developmental potential resembles that of early embryonic cells, can develop into cell types derived from the neuroectoderm, mesoderm, and endoderm. In the present study, we have shown a unique strategy to enhance SMC differentiation in P19 cells. Under chemical induction of high concentrations of retinoic acid (1 micromol/L), P19 cells showed optimum differentiation into SMCs. Because the P19 cells thus induced also showed differentiation into neuronal cells, a strategy to block neuronal lineage differentiation was developed using a stable transformant antisense RNA construct against Brn-2, a neuronal lineage-specific POU-domain transcription factor; thus, by specifically inhibiting neuronal differentiation, enhanced SMC differentiation by P19 cells was attained. SMC expression was confirmed by immunohistochemical staining, RNA analysis (RNase protection assay), and protein analysis (Western blot) using SMC-specific markers (eg, SM1 and calponin) and alpha-smooth muscle actin. Our results show that the pathway of SMC differentiation may provide an in vitro system useful in the investigation of SMC regulatory mechanisms (eg, transcriptional regulation) and in the further understanding of SMC development and differentiation.

Quantum Capacity of Noisy Quantum Channel

In quantum communication theory, the quantum mutual entropy [4] is an important tool to analyse the efficiency of information transmission. It is the amount of information correctly transmitted from an input system to an output system through a quantum channel. The supremum of the quantum mutual entropy over a certain set of states with a fixed quantum channel is the quantum capacity of the channel. The capacity for quantum systems has been discussed in several papers, like [1,2,12]. In [8], we studied the quantum capacity for purely quantum channels.

Dynamical Entropy Through Quantum Markov Chains

Classical dynamical entropy is an important tool to analyze communication processes. For instance, it may represent a transmission capacity for one letter. In this paper, we formulate the notion of dynamical entropy through a quantum Markov chain and calculate it for some simple models.

A new treatment of communication processes with Gaussian channels

In order to discuss communication processes consistently for a Gaussian input with a Gaussian channel on an infinite dimensional Hilbert space, we introduce the entropy functional of an input source and the mutual entropy functional for a Gaussian channel and show a fundamental inequality for communication processes.

Note on quantum dynamical entropies

Abstract Classical dynamical entropy is an important tool to analyse the efficiency of information transmission in communication processes. Quantum dynamical entropy was first studied by Connes, Stormer and Emch. Since then, there have been many attempts to formulate or compute the dynamical entropy for some models. Here we review four formulations due to 1. (a) Connes, Narnhofer and Thirring, 2. (b) Ohya, 3. (c) Accardi, Ohya and Watanabe, 4. (d) Alicki and Fannes. We consider mutual relations between these formulations and we show some concrete computations for a model.

Efficiency of optical modulations with coherent state

In information of communication by means of laser, quantum communication theory describing the quantum effect has been needed instead of conventional Shannons theory. In this paper, (1) we briefly review the mathematical formulation of quantum communication theory and (2) consider the efficiency of modulations (ASK(OOK), FSK, PSK, PPM) with coherent state by using the Ohyas mutual entropy.

A Mathematical Study of Information Transmission in Quantum Communication Processes

In quantum communication theory, an input signal is represented by the quantum state. The input state changes under the influence of noise and loss associated with a channel. The attenuation process is a model of quantum channel describing an optical communication process. When an input state changes to an output state through a channel, the amount of information carried from the input state to the output state is represented by the quantum mutual entropy (information). The quantum communication theory has been studied by various researchers [4–7,11,13,15,16,18].

On the mathematical treatment of the Fredkin-Toffoli-Milburn gate

Abstract We reformulate the Fredkin-Toffoli-Milburn (FTM) gate as a quantum channel and by calculating the quantum mutual entropy, we rigorously prove that information is conserved for the FTM gate.