• Journal of Microbiology and Biotechnology
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• 제10권6호
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• pp.844-850
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• 2000

The specific binding and internalization of viral particles is an essential step for the successful infection of viral pathogens. In the case of the hepatitis B virus (HBV), virions bind to the host cell via the preS domain of the viral surface antigen and are subsequently internalized by endocytosis. HBV-preS specific receptors are primarily expressed on hepatocytes, however, viral DNA and proteins have also been detected in extrahepatic sites, suggsting that celluar recepators for HBV may also exist on extrahepatic cells. Recently, an EBV-transformed B-cell line was identified onto which the preS region binds in a receptor-ligand specific manner. In this study, this specific interaction was further characterized, and the binding region within the preS protein was locaized. Also the internalization after host cell attachment was visualized and analyzed by fluorescence-labeled HBV-preS1 proteins using confocal microscopy. Energy depletion by sodium azide treatment effectively inhibited the internalization of the membrane-bound preS1 ligands, thereby indicating an energy-dependent receptor-mediated endocytotic pathway. Accordingly, the interaction of HBV-pres! with this specific B-cell line may serve as an effective model for an infection pathway in extrahepatic cells.

• BMB Reports
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• 제29권2호
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• pp.175-179
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• 1996

Viral surface proteins are known to play an essential role in attachment of the virus particle to the host cell membrane. In case of the hepatitis B virus (HBV) several reports have described potential receptors on the target cell side, but no definite receptor protein has been isolated yet. As for the viral side, it has been suggested that the preS region of the envelope protein, especially the preS1 region, is involved in binding of HBV to the host cell. In this study, preS1 region was recombinantly expressed in the form of a maltose binding protein (MBP) fusion protein and used to identify and visualize the expression of putative HBV receptor(s) on the host cell. Using laser scanned confocal microscopy and by FACS analysis, MBP-preS1 proteins were shown to bind to the human hepatoma cell line HepG2 in a receptor-ligand specific manner. The binding kinetic of MBP-preS1 to its cellular receptor was shown to be temperature and time dependent. In cells permeabilized with Triton X-100 and treated with the fusion protein, a specific staining of the nuclear membrane could be observed. To determine the precise location of the receptor binding site within the preS1 region, several short overlapping peptides from this region were synthesized and used in a competition assay. In this way the receptor binding epitope in preS1 was revealed to be amino acid residues 27 to 51, which is in agreement with previous reports. These results confirm the significance of the preS1 region in virus attachment in general, and suggest an internalization pathway mediated by direct attachment of the viral particle to the target cell membrane.

• 생명과학회지
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• 제22권9호
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• pp.1201-1206
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• 2012

Crlz1 유전자는 B 세포 분화 과정 중 pre-B 세포 분화 단계에서 특이적으로 발현됨이 밝혀져 있다. Crlz1 유전자의 발현과 연관되는 3개의 DNase I hypersensitive site (HSS8, 9, 10)가 Crlz1 유전자의 전사 시작점으로부터 바로 위쪽의 chromatin 상에서 발견되었고, 그 중에서 HSS9/10은 Crlz1 promoter 지역에 해당하며 매우 높은 전사 활성을 가지는 것으로 이미 보고 되었다. 본 연구에서는 앞의 연구에서 더 나아가 HSS8이 Crlz1 promoter의 전사활성을 약 2 배 증가시키는 enhancer의 역할을 하고 있는 현상을 밝혔으며, 또한 HSS8의 위치가 Crlz1 유전자의 전사 시작점을 기준으로 하였을 때 -1055와 -1159 사이, 즉 104 bp 길이의 chromatin DNA 상에 존재하며, 이러한 HSS8의 위치는 luciferase reporter의 활성 측정으로 비교 분석되어진 deletion construct들의 전사 활성에 대한 결과와도 잘 부합되었다.

• 약학회지
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• 제45권6호
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• pp.708-714
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• 2001

Many studies have provided evidences that hepatitis B surface antigen (HBsAg) including preS region could be an ideal candidate for a new hepatitis B virus (HBV) vaccine with higher efficacy. We established CHO cell lines, IY-CHO-2 and IY-CHO-11 expressing high levels of HBsAg containing preS2 and S protein by stable transfection method. These cell lines expressed the correct size (about 1 kb in length) of HBsAg mRNA as expected. The purified protein from the culture supernatants of the clones showed the same sizes as those expressed in native hepatitis B virus (24 kDa, 27 kDa, 34 kDa and 36 kDa). Antibody productivity of CHO-derived HBsAg protein at lower dose challenge was higher than the protein containing S region alone expressed in yeast system. These results indicate that CHO-derived HBsAg protein containing preS2 and S region can be effectively used for a better immune response as a HBV vaccine.

• Asian-Australasian Journal of Animal Sciences
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• 제32권12호
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• pp.1844-1853
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• 2019

Objective: We investigated how pituitary adenylate cyclase-activating polypeptide (PACAP) affects embryonic development during pre-in vitro maturation (pre-IVM) using porcine oocytes isolated from small follicles. Methods: We divided the follicles into the experimental groups by size (SF, small follicles; MF, medium follicles) and treated with and without PACAP and cultured for 18 hours (PreSF[-]PACAP; without PACAP, Pre-SF[+]PACAP; with PACAP) before undergoing IVM. The gene expression related to extracellular matrix formation (amphiregulin, epiregulin, and hyaluronan synthase 2 [HAS2]) and apoptosis (Bcl-2-associated X [BAX], B-cell lymphoma 2, and cysteine-aspartic acid protease 3) was investigated after maturation. The impact on developmental competence was assessed by the cleavage and blastocyst rate and total cell number of blastocysts in embryos generated from parthenogenesis (PA) and in vitro fertilization (IVF). Results: Cleavage rates in the Pre-SF(+)PACAP after PA were significantly higher than SF and Pre-SF(-)PACAP (p<0.05). The cleavage rates between MF and Pre- SF(+)PACAP groups yielded no notable differences after IVF. Pre-SF(+)PACAP displayed the higher rate of blastocyst formation and greater total cell number than SF and Pre-SF(-)PACAP (p<0.05). Cumulus cells showed significant upregulation of HAS2 mRNA in the Pre-SF(+)PACAP compared to the SF (p<0.05). In comparison to other groups, the Pre-SF(+)PACAP group displayed a downregulation in mRNA expression of BAX in matured oocytes (p<0.05). Conclusion: The PACAP treatment during pre-IVM improved the developmental potential of porcine oocytes derived from SF by regulating cumulus expansion and apoptosis of oocytes.

• 대한수의학회지
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• 제52권4호
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• pp.269-273
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• 2012

In the present study, we investigated the expression patterns of ErbB family proteins in the pre-pubertal and pubertal mammary glands of dairy cows in association with gland development. For this study, we performed immunohistochemistry for ErbB-1-4 and Ki-67 cell proliferation marker. We found that the pre-pubertal and pubertal mammary glands had typical structures, including ducts and terminal end buds embedded in the stroma, and no development of lobuloalveolar structures. On immunohistochemistry, ErbB-2 and ErbB-3 were strongly expressed in the cytoplasm and nuclei in the epithelial cells of mammary ducts and terminal end buds, and stromal cells, whereas ErbB-1 and ErbB-4 were weakly expressed only in the cytoplasm of gland epithelium and stromal cells, irrespective of the developmental stage. Cell proliferation was inactive in the mammary gland cell compartments in both phases. Thus, expression of the ErbB family in the developing mammary glands was not associated with their functional effects, such as cell proliferation and lobuloalveolar development. In conclusion, ErbB receptors were differentially expressed in the epithelial and stromal cells of virgin mammary glands of dairy cows. Compared with rodent mammary glands, ErbB-3 and ErbB-4 were found to be highly expressed in bovine mammary glands.

• The Korean Journal of Physiology and Pharmacology
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• 제15권3호
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• pp.179-187
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• 2011

Regulation of B cell receptor (BCR)-induced $Ca^{2+}$ signaling by CD40 co-stimulation was compared in long-term BCR-stimulated immature (WEHI-231) and mature (Bal-17) B cells. In response to long-term pre-stimulation of immature WEHI-231 cells to ${\alpha}$-IgM antibody (0.5~48 hr), the initial transient decrease in BCR-induced $[Ca^{2+}]_i$ was followed by spontaneous recovery to control level within 24 hr. The recovery of $Ca^{2+}$ signaling in WEHI-231 cells was not due to restoration of internalized receptor but instead to an increase in the levels of $PLC{\gamma}2$ and $IP_3R-3$. CD40 co-stimulation of WEHI-231 cells prevented BCR-induced cell cycle arrest and apoptosis, and it strongly inhibited the recovery of BCR-induced $Ca^{2+}$ signaling. CD40 co-stimulation also enhanced BCR internalization and reduced expression of $PLC{\gamma}2$ and $IP_3R-3$. Pre-treatment of WEHI-231 cells with the antioxidant N-acetyl-L-cysteine (NAC) strongly inhibited CD40-mediated prevention of the recovery of $Ca^{2+}$ signaling. In contrast to immature WEHI-231 cells, identical long-term ${\alpha}$-IgM pre-stimulation of mature Bal-17 cells abolished the increase in BCR-induced $[Ca^{2+}]_i$, regardless of CD40 co-stimulation. These results suggest that CD40-mediated signaling prevents antigen-induced cell cycle arrest and apoptosis of immature B cells through inhibition of sustained BCR-induced $Ca^{2+}$ signaling.

• 한국통신학회논문지
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• 제19권6호
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• pp.1085-1094
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• 1994

본 논문에서는 망 노드에서의 폭주를 B-ISDN UNI에서 예방하기 위해 B-NT에서 일시적인 셀 저장 및 선택적 셀 폐기를 수행하는 트래픽 흐름 제어를 제안하였다. 제안된 구조는 B-NT 시스템에서 T 접속을 향하는 출력 셀 흐름을 감소 또는 억제시키도록 구성하고, 인접 망 노드의 상태를 정상, 준폭주, 폭주의 세상태로 정의하였다. 준폭주 상태에서는 손실에 민감한 트래픽은 일시적으로 저장되어 출력 셀 흐름의 속도를 저하시키고, 폭주 상태에서는 손실에 민감한 트래픽의 셀 저장과 더불어 지연에 민감한 트래픽의 셀이 선택적으로 폐기되어 최대한 출력 트래픽 흐름을 억제시킨다. 입력 셀 흐름과 망 노드 상태의 변화를 IBP와 3 상태 마르코프 체인으로 모델링하여 B-NT 시스템에서 제안된 구조의 성능 분석을 위한 시뮬레이션을 수행하여 적당한 버퍼 사이즈를 구하고 망 노드의 상태에 따른 제안한 구조의 성능 변화를 조사한 결과 망 노드에서의 폭주 정도가 극심한 경우에는 제안한 방법으로 제어가 거의 불가능하지만, 그 외의 경우에는 2,000셀 이상의 버퍼 사이즈로 제어가 가능함을 알 수 있었다.

• BMB Reports
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• 제29권2호
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• pp.180-182
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• 1996

One of the essential functions of virus surface proteins is the recognition of specific receptors on target cell membranes, and cellular receptors play an important role in viral pathogenesis. But the earliest steps of hepatitis B virus (HBV) infection, such as hepatocyte receptor interaction with the virus, are poorly understood. Previous work has suggested an important role of the preS1 region of HBV envelope protein in mediating viral binding to hepatocytes. Although hepatitis B virus (HBV) infection appears to be initiated by specific binding of virions to cell membrane structures via one or potentially several viral surface proteins, data showing the identification or isolation of the HBV receptor (s) are not yet available. The receptor-like proteins on the plasma membrane surface of HepG2 cells that bind to PreS1 were separated and identified using affinity chromatography, and the amino-terminal amino acid sequences of the receptor-like proteins were determined.

• 한국식품영양과학회지
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• 제33권2호
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• pp.271-277
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• 2004

최근에 방사선 조사에 대해 방호효과를 가지는 것으로 알려진 보중익기탕의 골수세포 분화 유도 효과에 대해 관찰하였다. 시험관에서 골수세포를 배양했을 때, 배양시간(5일,10일)에 따라 대조군의 세포 수는 현저히 감소하였고, 보중익기 탕의 total 분획을 첨가하였을 때도 비슷한 결과를 얻었다. 그러나 polysaccaride 분획을 첨가하였을 때는 감소하는 세포수가 일정한수준에서 유지되며 더 이상 감노하지 않았다. 그리고 이들 세포가 어떤 종류의 세포인지를 유세포분석기로 분석한 결과, Pre-B세포의 특징적인 세포 표면 단백질인 CDl9와 CD40을 동시에 발현한 세포인 것이 확인되었다. 또한, 이들 세포는 분화과정 이 끝난 B세포가 분비하는 IgM 뿐만 아니라 IgG1, G2a, G3를 분비하였다. 이상의 결과 보중익기탕의 polysaccaride 분획에 골수세포가 B세포로 분화 증식하는 것을 유도하는 성분이 포함되어 있어 방사선 조사로 상해를 입은 조혈계에 대한 방호 효과를 나타내는 것으로 생각된다.