• 제목/요약/키워드: telomere

검색결과 135건 처리시간 0.067초

Telomerase reverse transcriptase in the regulation of gene expression

  • Zhou, Junzhi;Ding, Deqiang;Wang, Miao;Cong, Yu-Sheng
    • BMB Reports
    • /
    • 제47권1호
    • /
    • pp.8-14
    • /
    • 2014
  • Telomerase plays a pivotal role in the pathology of aging and cancer by maintaining genome integrity, controlling cell proliferation, and regulating tissue homeostasis. Telomerase is essentially composed of an RNA component, Telomerase RNA or TERC, which serves as a template for telomeric DNA synthesis, and a catalytic subunit, telomerase reverse transcriptase (TERT). The canonical function of TERT is the synthesis of telomeric DNA repeats, and the maintenance of telomere length. However, accumulating evidence indicates that TERT may also have some fundamental functions that are independent of its enzymatic activity. Among these telomere-independent activities of hTERT, the role of hTERT in gene transcription has been investigated in detail. Transcriptional regulation is a fundamental process in biological systems. Several studies have shown a direct involvement of hTERT in gene transcription. This mini-review will focus on the role of hTERT in gene transcription regulation, and discuss its possible mechanisms.

Investigating the role of Sirtuins in cell reprogramming

  • Shin, Jaein;Kim, Junyeop;Park, Hanseul;Kim, Jongpil
    • BMB Reports
    • /
    • 제51권10호
    • /
    • pp.500-507
    • /
    • 2018
  • Cell reprogramming has been considered a powerful technique in the regenerative medicine field. In addition to diverse its strengths, cell reprogramming technology also has several drawbacks generated during the process of reprogramming. Telomere shortening caused by the cell reprogramming process impedes the efficiency of cell reprogramming. Transcription factors used for reprogramming alter genomic contents and result in genetic mutations. Additionally, defective mitochondria functioning such as excessive mitochondrial fission leads to the limitation of pluripotency and ultimately reduces the efficiency of reprogramming. These problems including genomic instability and impaired mitochondrial dynamics should be resolved to apply cell reprograming in clinical research and to address efficiency and safety concerns. Sirtuin (NAD+-dependent histone deacetylase) has been known to control the chromatin state of the telomere and influence mitochondria function in cells. Recently, several studies reported that Sirtuins could control for genomic instability in cell reprogramming. Here, we review recent findings regarding the role of Sirtuins in cell reprogramming. And we propose that the manipulation of Sirtuins may improve defects that result from the steps of cell reprogramming.

Exploiting tumor cell senescence in anticancer therapy

  • Lee, Minyoung;Lee, Jae-Seon
    • BMB Reports
    • /
    • 제47권2호
    • /
    • pp.51-59
    • /
    • 2014
  • Cellular senescence is a physiological process of irreversible cell-cycle arrest that contributes to various physiological and pathological processes of aging. Whereas replicative senescence is associated with telomere attrition after repeated cell division, stress-induced premature senescence occurs in response to aberrant oncogenic signaling, oxidative stress, and DNA damage which is independent of telomere dysfunction. Recent evidence indicates that cellular senescence provides a barrier to tumorigenesis and is a determinant of the outcome of cancer treatment. However, the senescence-associated secretory phenotype, which contributes to multiple facets of senescent cancer cells, may influence both cancer-inhibitory and cancer-promoting mechanisms of neighboring cells. Conventional treatments, such as chemo- and radiotherapies, preferentially induce premature senescence instead of apoptosis in the appropriate cellular context. In addition, treatment-induced premature senescence could compensate for resistance to apoptosis via alternative signaling pathways. Therefore, we believe that an intensive effort to understand cancer cell senescence could facilitate the development of novel therapeutic strategies for improving the efficacy of anticancer therapies. This review summarizes the current understanding of molecular mechanisms, functions, and clinical applications of cellular senescence for anticancer therapy.

The Pleiotropy of Telomerase against Cell Death

  • Sung, Young Hoon;Choi, Yoon Sik;Cheong, Cheolho;Lee, Han-Woong
    • Molecules and Cells
    • /
    • 제19권3호
    • /
    • pp.303-309
    • /
    • 2005
  • The end of eukaryotic genomic DNA is capped by a specialized structure called as "telomere" which consists of the repetitive array of nucleotide sequence, TTAGGG, in humans and mice, and a variety of binding proteins. Telomerase is a ribonucleoprotein (RNP) complex responsible for the elongation of telomeres to maintain the genomic integrity, and is composed of telomerase reverse transcriptase (TERT), telomerase RNA component (TERC), and their associated factors regulating the catalytic activity of telomerase. Although it is now apparent that telomerase protects cells from apoptosis via the maintenance of genomic integrity by stabilizing telomeres, our understanding for the physiological role of telomerase is yet far from completion, and emerging evidence suggests that telomerase has additional extratelomeric roles in mediating cell survival and anti-apoptotic functions against various cytotoxic stresses. Here we summarize and discuss how telomerase and telomeres are involved in mediating cellular protection against apoptosis.

닭의 품종 간 스트레스 반응 정도 비교 분석 (Comparison of Stress Response between Korean Native Chickens and Single Comb White Leghorns subjected to a High Stocking Density)

  • 손시환;조은정;박단비;장인석;문양수
    • 한국가금학회지
    • /
    • 제41권2호
    • /
    • pp.115-125
    • /
    • 2014
  • 본 연구에서는 닭의 품종에 따른 개체의 스트레스 반응정도를 알아보고자 한국 재래닭과 단관 백색 레그혼종을 공시하고, 고밀도 사육에 따른 생리적 스트레스 표지 값을 비교 분석하였다. 스트레스 반응 정도는 혈액과 각 조직별 세포들에 대한 텔로미어 함량, DNA 손상율 및 열 스트레스 단백질(HSPs) 유전자의 발현율을 분석하고 비교하였다. 텔로미어 함량 및 감축율은 양적 형광 접합 보인법으로 분석하였고, DNA 손상율은 Comet assay로 분석하였다. 열 스트레스 단백질 유전자 발현율은 HSP70, HSP90-${\alpha}$, HSP90-${\beta}$ 및 HMGCR을 표적으로 하여 real-time PCR로 분석하였다. 분석 결과, 한국 재래닭과 단관 백색 레그혼 간 품종에 따른 체중, 증체량, 텔로미어 감축율 및 DNA 손상율의 차이는 없는 것으로 나타났다. 그러나 고밀도 사육과 같은 스트레스 사양 관리는 품종에 상관없이 닭의 성장을 저해하고, 텔로미어 감축 및 DNA 손상을 촉진시키는 것으로 나타났다. 한편, HMGCR을 제외한 HSPs 유전자 발현율의 경우, 밀사 사육에 따른 요인뿐만 아니라, 품종 간에도 유의적 차이를 보였다. HSPs의 분석에 따른 스트레스 정도는 단관 백색 레그혼종이 한국 재래닭에 비해 보다 민감하게 반응하는 것으로 나타났다. 따라서 품종과 관계없이 닭에 있어 고밀도 사육이 강한 환경적 스트레스 요인임을 시사하고, 품종 간 스트레스의 반응 정도는 레그혼종이 한국 재래닭에 비해 다소 높은 것으로 사료된다.

인체폐암세포에서 봉독에 의한 prostagladin E2 생성 및 telomerase 활성 저하 (Bee Venom-induced Growth Inhibition of Human Lung Cancer Cells was Associated with Inhibition of Prostagladin E2 Production and Telomerase Activity.)

  • 김종환;황원덕;김병우;최영현
    • 생명과학회지
    • /
    • 제19권4호
    • /
    • pp.502-507
    • /
    • 2009
  • 본 연구에서는 봉독의 처리에 따른 A549 폐암세포의 증식억제에서 $PGE_2$ 생성 및 telomerase 활성의 변화 관련성을 조사하였다. A549 세포의 증식은 봉독 처리에 의하여 유의적으로 감소되었으며, 이는 apoptosis 유발과 연관성이 있음을 알 수 있었다. 봉독 처리 농도의 증가에 따라 COX-2의 발현이 전사 및 번역 수준에서 모두 감소되었으며 이에 따른 $PGE_2$의 생성이 현저하게 감소되었으나, COX-1의 발현에는 큰 변화가 없었다. 또한 봉독 처리에 따라 telomere 조절인자들 중, hTERT, hTR 및 c-myc의 발현이 억제되었으며, telomerase의 활성도 매우 감소되었다. 본 연구의 결과는 $PGE_2$ 생성과 telomerase 활성 저하가 봉독의 항암 작용 표적인자로서 작용될 수 있음을 보여준다.