• Journal of Life Science
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• v.11 no.5
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• pp.400-404
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• 2001

A new human endogenous retroviral family (HERV-S) has recently been identified from human X chromosome. It is 6.7 kb in length and has a typical retroviral structure with LTR-gag-pol-env-LTR. Using the PCR and sequencing approach, we investigated LTR elements of the HERV-S family from a human genomic DNA. Four LTR elements (HSL-1, HSL-5, HSL-10, HSL-11) were identified and have a high degree of sequence similarity(96-99%) with that of the HERV-S. Phylogenetic analysis from the HERV-S family indicated that the LTR elements were mainly divided into 2- groups through evolutionary divergence in the primate evolution. Further investigation of the HERV-S LTR elements in primates may cast light on the integration timing into the primate genome and understanding of human evolution.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.4
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• pp.40-47
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• 2001

In this pater, the QLQG/LTR control method is applied for the position control of the nonlinear timing belt driving sys-tem. Parameters fo the plant are identified by genetic algorithm and nonlinear elements, such as Coulomb friction and dead-zone, and quasi-linearized by RIDE method. Comparing with the LQG/LTR contro. the QLQG/LTR has similar structures of the LQG/LTR, but this method can consider nonlinear effects in designing the controller. Thus, the QLQG/LTR control system is robust to hard nonlinearities such as Coulomb friction, dead-zone, etc. Forma given hard non-linear system through experiments, it is shown that the tracking performance of the QLQG/LTR control system can be very improved that the LQF/LTR control system.

• Animal cells and systems
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• v.6 no.2
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• pp.167-170
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• 2002

The long terminal repeats (LTRs) of human endogenous retrovirus (HERV) have been found to be coexpressed with sequences of closely located genes. It has been suggested that the LTR elements have contributed to the structural change or genetic variation of human genome connected to various diseases and evolution. We examined the HERV-W LTR elements in various cancer cells (2F7, A43l , A549, HepG2, MIA-PaCa-2, PC-3, RT4, SiHa, U-937, and UO-31). Using genomic DNA from the cancer cells, we performed PCR amplification and identified twelve new HERV-W LTR elements. Those LTR elements showed a high degree of sequence similarity (88-99％) with HERV-W LTR (AF072500). A phylogenetic tree obtained by the neighbor-joining method revealed that HERV-W LTR elements could be mainly divided into two groups through evolutionary divergence. Three HERV-W LTR elements (RT4-2, A43l-1, and UO3l-2) belonged to Group 1, whereas nine LTR elements (2F7-2, A549-1, A549-3, HepG2-3, MP2-2, PC3-1, SiHa-8, SiHa-10, and U937-1) belonged to Group 11. Taken together, our new sequence data of the HERV-W LTR elements may contribute to an understanding of tissue-specific cancer by genomic instability of LTR integration.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.118-127
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• 1993

A nonlinear control design method called the QJQG/LTR method is presented for the depth control of underwater vehicles with the deadzone of the flow control valve. And, it is shown how the design plant model can be formulated in the QLQG/LTR depth control system design for underwater vehicles which have the triple integrator. In order to show the effectiveness of this control system, the linear LQG/LTR control system neglected the deadzone effect and the nonlinear QLQG/LTR control system considered it are compared. It is found that the QLQG/LTR control system is relatively insensitive to the input magnitude, even if there exists a hard nonlinearity in the plant.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.508-513
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• 2002

Human endogenous retroviral long terminal repeats (LTRs) have been found to be coexpressed with sequences of genes located nearby. It has been suggested that the LTR elements have contributed to the structural change or genetic variation of human genome connected to various diseases. The HERV-W family has been identified in the cerebrospinal fluids and brains of individuals with schizophrenia. Using a cDNA library derived from a human brain, the HERV-W LTR elements were examined and five new LTR elements were identified. These elements were examined using a YAC clone panel from the Xq21.3 region linked to psychosis that was replicated on the Y chromosome after the separation of the chimpanzee and human lineages. Fourteen elements of the HERV-W LTR were identified in that region. Those LTR elements showed a high degree of sequence similarity ($91.8-99.5\%$) with previously reported HERV-W LTR. A phylogenetic tree obtained from the neighbor-joining method revealed that new HERV-W LTR elements were closely related to the AXt000960, AF072504, and AF072506 from the GenBank database. The data indicates that several copy numbers of the HERV-W LTR elements exist on the Xq21.3 region and are also expressed in the human brain. These LTR elements need to be further investigated as potential leads to neuropsychiatric diseases.

• YAKHAK HOEJI
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• v.52 no.2
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• pp.125-130
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• 2008

The long terminal repeat (LTR) of retroviral DNA genome plays an important role in the integration process by providing substrate recognition site for viral integrase (IN). The dinucleotide CA near the 3'-end of the LTR termini is completely conserved among retoviruses. In order to study specificity of interaction between prototype foamy virus (PFV) IN and its U5 LTR DNA, the effect of mutagenesis of the CA sequence was investigated by studying reactivity of PFV IN to the mutant LTR substrates. Replacement of only the C or the A allowed 60 to 100% of the reactivity of the wild type LTR substrate. In addition, replacement of the C and the A showed 50 to 80% of the reactivity of the wild type LTR substrate, indicating that PFV IN has less specificity on the conserved CA sequence when it is compared to the other retroviral INs. Therefore it is suggested that PFV IN is less dependent on the conserved sequence of LTR termini for its enzymatic reaction.

• Journal of Life Science
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• v.10 no.1
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• pp.32-36
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• 2000

Solitary long terminal repeats(LTRs) of human endogenous retrovirus K family(HERV-K) have been found to be coexpressed with sequences of closely located genes. It has been suggested that HERV-K LTR-like elements entered the primate genome approximately 33-40 million years ago. WE investigated the presence of HERV-K LTR elements in New World monkeys using PCR amplification. Six LTR elements of HERV-K family were identified from New World monkeys, represented by the squirrel and night monkeys. They showed a high degree of sequence homology(96-99%) with the human-specific HERV-K LTR elements. Phylogenetic analysis reveals that an LTR element (SM-1) from the squirrel monkey and another LTR element (NM-1) from the night monkey are very closely related to the human-specific HERV-K LTR elements with low degree of divergence. This finding suggests that some of LTR elements of HERV-K family have recently been proliferated in New World monkeys. A sequence in chromosome Xq26(AL034407) \ulcorner contains an HERV-K LTR element was shown to be present in the human genome, but is absent in the bonobo, chimpanzee, gorilla, orangutan, and gibbon. It has more than 99% homology to other human-specific HERV-K LTR elements. This sequence thus represents and isolated insertion of an evolving class of elements that may have made a particular contribution to human genomic plasticity.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.38-45
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• 1999

In this paper, A novel approach on $H_{\infty}-LTR$ design scheme is presented. The proposed scheme provides a design toll which can trade-off the recovery error against the control input. In the first stage, Kalman filter is designed to shape the loop to satisfy the required performance specifications. The designed Kalman filter, together with the plant transfer function, is used as a target transfer function. In the second stage, sensitivity function weighted $H_{\infty}-LTR$suboptimal LTR is designed to recover the target loop transfer function. Simulation results of LQG/LTR, $H_{\infty}-LTR$are compared to demonstrate the good property of the proposed scheme.

• Journal of Life Science
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• v.11 no.2
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• pp.83-86
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• 2001

The long terminal repeat (LTR) elements of human endogenous retrovirus (HERV) have been found to be coexpressed with genes located nearby. It has been suggested that the LTR elements have contributed to the genetic variation of human genome connected to various diseases. Recently, HERV-W family was identified in the cerebrospinal fluids and brains of individuals with schizophrenia. Using genomic DNAs derived from schizophrenia, we performed PCR amplification and identified six HERV-W LTR elements. Those LTR elements showed a high degree of sequence similarity (87.7-99.5%) with HERV-W LTR (AF072500). Sequence analysis of the HERV-W LTR elements revealed that clone W-sch1 showed identical sequence with the AC003014 (PAC clone RP1-290B4) derived from human Xq23. Clone W-sch2 was closely related to the AC0072442 derived from human Y chromosome by phylogenetic analysis. Our data suggest that new HERV-W LTR elements in schizophrenia may be very useful for further studies to understand neuropsychiatric diseases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.10
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• pp.981-991
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• 1991

LQG/LTR method suggested to improve robustness of LQG have a theoritical constraint that it cannot apply to nonminimum phase plant(NMP). In this paper, we suggest a new LQG/LTR method for NMP which consist of three design steps. The first step is design a additional feed-foward compensator which approximate the given NMP plant to minimum phase(MP) plant and the next step is design a target loop transfer function for approximated MP plant satisfying the design specifications such as robust-performance and robust-stability. The last step is loop transfor recovery(LTR) that the open loop transfer function recovers the terget loop. It was shown by simulation example that the suggested method can solve the NMP constraint in designing LQG/LTR.