• BMB Reports
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• 제54권8호
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• pp.413-418
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• 2021

ErbB3-binding protein 1 (EBP1) is a multifunctional protein associated with neural development. Loss of Ebp1 leads to upregulation of the gene silencing unit suppressor of variegation 3-9 homolog 1 (Suv39H1)/DNA (cytosine 5)-methyltransferase (DNMT1). EBP1 directly binds to the promoter region of DNMT1, repressing DNA methylation, and hence, promoting neural development. In the current study, we showed that EBP1 suppresses histone methyltransferase activity of Suv39H1 by promoting ubiquitin-proteasome system (UPS)-dependent degradation of Suv39H1. In addition, we showed that EBP1 directly interacts with Suv39H1, and this interaction is required for recruiting the E3 ligase MDM2 for Suv39H1 degradation. Thus, our findings suggest that EBP1 regulates UPS-dependent degradation of Suv39H1 to govern proper heterochromatin assembly during neural development.

• Molecules and Cells
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• 제44권12호
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• pp.861-878
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• 2021

The human genome contains many retroviral elements called human endogenous retroviruses (HERVs), resulting from the integration of retroviruses throughout evolution. HERVs once were considered inactive junk because they are not replication-competent, primarily localized in the heterochromatin, and silenced by methylation. But HERVs are now clearly shown to actively regulate gene expression in various physiological and pathological conditions such as developmental processes, immune regulation, cancers, autoimmune diseases, and neurological disorders. Recent studies report that HERVs are activated in patients suffering from coronavirus disease 2019 (COVID-19), the current pandemic caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection. In this review, we describe internal and external factors that influence HERV activities. We also present evidence showing the gene regulatory activity of HERV LTRs (long terminal repeats) in model organisms such as mice, rats, zebrafish, and invertebrate models of worms and flies. Finally, we discuss several molecular and cellular pathways involving various transcription factors and receptors, through which HERVs affect downstream cellular and physiological events such as epigenetic modifications, calcium influx, protein phosphorylation, and cytokine release. Understanding how HERVs participate in various physiological and pathological processes will help develop a strategy to generate effective therapeutic approaches targeting HERVs.

• Parasites, Hosts and Diseases
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• 제24권1호
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• pp.42-48
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• 1986

As a series of systematic classification of paramphistomes, in the first step, paramphistomes in the lumen and reticulum were collected on 170 Korean catties (2∼3 years age, male) slaughtered at Jeonju abattoir from July, 1984 to September, 1985 and were classified by means of morphology of the worms. Afterwards, the karyotype of Paramphistomum explanatum (Creplin, 1849) which is the common in Korean cattle was detected by means of modified air-drying method from testis cells of the worm. The following is a brief summary of the leading facts gained through the experiment. 1. Most of the cattle slaughtered at the abattoir were infected with paramphistomes. The 5 species of the worms were detected on 170 Korean cattle and the worm burden per head was from 2 to 784(on the average 170) worms, 120(70.59%) heads out of them involving 2∼100 worms. In 28,900 individuals of paramphistomes obtained on 170 Korean cattle, appearance rates of various worms were as follows : 49.74% in P. explanatum, 48.08% in P. cervi, 0.98% in Orthocoelium orthocoelium, 0.89% in Fischoederius cobboldi and 0.14% in Cotylophoron cotylcphorum. 2. The chromosome number of 620 P. explanatum in the haploid and diploid cells was n=9 and 2n=18, and abundant cells in meiotic division were observed; 1,420 haploid and 38 diploid cells were reliable. Nine pairs of mitotic chromosomes were homologous and the chromosomes were composed of aye medium-sized metacentrics(m), subtelocentrics(st) or submetacentrics(sm) and four smallsized subtelocentrics(st) or submetacentrics(am), while meiotic metaphase chromosomes were composed of five medium and four small-sized. 3. The haploid of the testis cells showed C-band in the centromeric region from 8 of them, whereas the remaining chromosome No. 5 included heterochromatin on the tip region, and chromosomes No. 3 and No. 7 showed a remarkable C-band distinguished from other chromosomes.

• Applied Microscopy
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• 제24권3호
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• pp.55-66
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• 1994

This study was carried out to investigate the histological changes of sperm cells in testis, obtained from 100 of 3-year-old male rainbow trout (Oncorhynchus mykiss) collected and analysed from March in 1992 to February in 1993. Especially, the ultrastructural changes of spermatogonia, primary and secondary spermatocytes, spermatids, and spermatozoa were examined to describe the reproductive cycles of this species. The results obtained in this study were as follows: The ultrastructures of the gonadotrophs largely parallel the cyclical changes in the testes. Each nest of cells belongs to one spermatogenetic stage, although nests at different stages can be found within the one lobule. At first keterochromatin is dispersed and then is condensed. In mature gamete, the nucleus is dense and homogeneous. The nuclear membrane appeared at the beginning of differentiation. In spermatogonia, Sertoli cells are located at the periphery of their cytoplasm. In the primary spermatocytes, the small mitochondria are abundant over the outer cytoplasm. During cell differentiation, the cytoplasm decreases and the nucleus increases. In spermatids, the protein masses moved towards the posterior part of the nucleus. In late spermatids, the two large mitochondria are located over the cytoplasm. In spermatozoa, two spheroidal mitochondria (about 145nm long) are situated in parallel between the nucleus and the axoneme. Spermatozoa mitochondria are assembled into an organized sheath surrounding the outer dense fibres and axoneme of the flagellar midpiece. The two centrioles are quite separate and the central pair and sheath complex of the flagellum is inserted into the base of the distal centriole.

• 대한세포병리학회지
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• 제9권1호
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• pp.69-78
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• 1998

There is a lot of difficulty in the diagnosis of follicular lesions of the thyroid by fine needle aspiration cytology(FNAC). The main purpose of this report is offering more guidance regarding the cytologic appearance to distinguish follicular neoplasm from nodular golfer and laying stress on the presence of mixed group. The histologic and cytologic findings of 23 follicular neoplasms and 13 nodular (adenomatous) getters were reviewed. Histologic specimens were classified into the microfollicular(MIF), mixed(MIX), and nodular getter(NG) groups. The comparison of histologic patterns with histologic diagnosis revealed that all the lesions with predominantly microfollicular, trabecular, or solid pattern were follicular carcinoma and all the lesions with predominantly macrofollicular pattern were nodular goiter. The distinguishing cytologic features for the MIF group were irregular cell arrangement in cell groups(100%, p=0.00001), absence of atrophic follicular cells(100%, p=0.0007), abundant microfollicles(100%, 0=0.002), pleomorphic nuclei(100%, p=0.002), not predominant syncytial smear pattern(100%, p=0.002), heterochromatin(100%, p=0.032), absence of macrofollicles(100%, p=0.038), scant colloid(100%, 0=0.04), clear back-ground(83%, p=0.00006), and uniform sized follicles(83%, p=0.014). And regular cell arrangement(honeycomb appearance) in cell groups(85%, p=0.0000), atrophic change of follicular cells(69%, p=0.0002), syncytial smear pattern(54%, p=0.000), monomorphic nuclei(85%, p=0.008), and hemorrhagic background(100%, p=0.027) were characteristic features of the NG group. Seventeen out of 36 cases(47%) were the MIX group composed of combined cytologic features of the MIF and NG groups. Therefore the frequent presence of the MIX group is considered to be main cause of the difficulty in the diagnosis of follicular lesions by FNAC. The mixed morphologic feature may support the hypothesis of a biologic 'continuum' between nodular goiter and follicular neoplasm of thyroid gland.

• 한국수의병리학회지
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• 제1권2호
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• pp.97-106
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• 1997

This study was carried out to investigate the testicular toxicity of environmental toxicant, 2-bromopropane(2-BP) recently caused occupational intoxication in Korea by light microscopy and electron microscopy. To evaluate the effect on spermatogenesis and find target germ cell 10 weeks old male Sprague-Dawley rats were treated with 5g/10m ℓ/kg/day of 2-bromopropane for 3 consecutive days orally and observed on day 1 or day 7 after treatment. 2-BP induced depletion of spermatogonia and early spermatocytes on stages I-IX or extensive degeneration of germ cells on the other stages on day 1. But extensive degeneration of germ cells without stage specificity was observed and round spermatid formed multinucleated giant cells in the lumen of seminiferous tubules on day 7. Electron microscopically Sertoli cells showed irregular shape of nucleus and cytoplasmic vauolation. And spermatocyte showed a extensive heterochromatin and cytoplasmic vacuolation. But there was no histopathological changes in the interstial cells. On the base of the results the target germ cell was spermatogonia in the early of the study but Srtoli cells also effected by high-dosed 2-BP in the late of the study.

• Molecules and Cells
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• 제26권1호
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• pp.93-99
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• 2008

Transcriptional silencing is regulated by promoter methylation and histone modifications such as methylation and acetylation. We constructed a Schizosaccaromyces pombe reporter strain, KCT120a, to identify modifiers of transcriptional silencing, by inserting the $ura4^+$ gene into a heterochromatic telomere region. Two compounds inhibited the activity of histone deacetylases, induced acetylation of histone H3 and caused apoptotic cell death in HeLa cells. Expression of gelsolin and $p21^{waf1/cip1}$ also increased, as it does in response to HDAC inhibitors such as TSA. Therefore, these compounds appear to be potent inhibitors of HDACs, and hence potential anti-cancer drugs. Our observations suggest that a yeast cell-based assay system for transcriptional silencing may be useful for identifying histone deacetylase inhibitors and other agents affecting chromatin remodeling.

• 한국동물학회지
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• 제33권2호
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• pp.222-230
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• 1990

한국산 청서(Sciunis vulgaris corea)와 다람쥐(Tamias sibiricus asiaticu)의 핵형을 일반 Giemsa- stain과 C-banding stain방법으로 분석하였다. 청서의 염색체 수는 2n=40이였으며 이 중 6쌍은 중부, 8쌍은 차중부, 3쌍은 차단부 그리고 2쌍은 단부 염색체이었고 X 염색체는 차중부,Y염색체는 acro또는 차단부 염색체로서 NF(arm number)=72(성염색체 제외)를 나타내었다. 다람쥐의 염색체 수는 2n=38이었으며 이 중 3쌍은 중부, 4쌍은 차중부, 5쌍은 차단부, 그리고 6쌍은 단부 염색체이었고 X염색체는 차중부, Y염색체는 중부염색체로서 NF=60을 나타내었다. C-banding분석결과, 청서의 염색체에서는 각 경우 대부분 동원체 (centromere)부위와 말단부(telomere)에 주로 구조적이질염색질이 분포하였고 다람쥐에서는 몇몇 염색체상(제2,3,9번)을 제외하고는 주로 동원체 부위에 구조적이직염색질이 분포하였다. 이러한 결과들로 보아 핵형상의 분화에 non-Robensonian 재배열과 구조적 이질염색질의 분포가 중요한 작용을 한 것으로 생각된다.

• 생명과학회지
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• 제13권6호
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• pp.958-969
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• 2003

인간 Y 염색체는 엄격히 부계 유전되고 그 길이의 대부분은 남성 감수분열 동안 교차가 일어나지 않는다. 비록 이영역이 비 재조합 영역 Y (non-recombining region Y: NRY)로 불려왔지만, 풍부한 재조합의 발견으로 그것은 남성 특이 영역 (male-specific region Y: MSY)으로 재 명명(命名)되었다. MSY는 이질염색질 (heterochromatin) 서열과 세가지 분류의 진정염색질 (euchromatin) 서열 (X-전위영역, X-퇴화영역, 증폭영역)이 모자이크화 되어있다. X-전위영역의 서열은 X 염색체의 상동 좌위와 약 99% 동일성을 가진다. X-퇴화영역 서열은 고대 상 염색체가 현대의 X와 Y 염색체로 진화되면서 남아 있는 부분이다. 증폭영역의 8개의 회문구조는 인간 Y염색체의 남성 특이영역의 4분의 1을 차지한다. 이들은 많은 정소 특이 유전자를 포함하고, 회문구조서열 사이의 상동성은 약 99.97%이다. 이 회문구조의 양쪽 팔은 계속되는 유전자 교환에 의해 유지되며, 서로 협력하여 진화된다. 새로 태어나는 남성당 평균 약 600 염기당 하나가 Y-Y유전자 교환을 겪고, 정소 특이적 다중유전자군의 진화에 중요한 역할을 한다.

• Molecules and Cells
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• 제23권3호
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• pp.349-356
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• 2007

Simple Sequence Repeats (SSRs) represent short tandem duplications found within all eukaryotic organisms. To examine the distribution of SSRs in the genome of Brassica rapa ssp. pekinensis, SSRs from different genomic regions representing 17.7 Mb of genomic sequence were surveyed. SSRs appear more abundant in non-coding regions (86.6%) than in coding regions (13.4%). Comparison of SSR densities in different genomic regions demonstrated that SSR density was greatest within the 5'-flanking regions of the predicted genes. The proportion of different repeat motifs varied between genomic regions, with trinucleotide SSRs more prevalent in predicted coding regions, reflecting the codon structure in these regions. SSRs were also preferentially associated with gene-rich regions, with peri-centromeric heterochromatin SSRs mostly associated with retrotransposons. These results indicate that the distribution of SSRs in the genome is non-random. Comparison of SSR abundance between B. rapa and the closely related species Arabidopsis thaliana suggests a greater abundance of SSRs in B. rapa, which may be due to the proposed genome triplication. Our results provide a comprehensive view of SSR genomic distribution and evolution in Brassica for comparison with the sequenced genomes of A. thaliana and Oryza sativa.