本文選題：Gadd45α + 單克隆��； 參考：《北京協(xié)和醫(yī)學(xué)院》2012年碩士論文

【摘要】：Gadd45為生長抑制和DNA損傷基因(Growth arrest and DNA damage inducible gene Gadd45)是由Fornace等[’]于1988年發(fā)現(xiàn)。Gadd45家族包括三個(gè)成員：Gadd45α (Gadd45α/Gadd45)、Gadd45b(Gadd45β/MyD118)、Gadd45g(Gadd45γ/CR6),它們是DNA損傷修復(fù)的重要相關(guān)基因,在細(xì)胞凋亡中發(fā)揮重要的作用[2-3]。Gadd45基因家族序列非常相似大約有57%基因同源性,通常在環(huán)境損傷因子作用后,隨之DNA修復(fù)途徑的啟動(dòng)而誘導(dǎo)產(chǎn)生。 Gadd45a蛋白是一個(gè)小球狀酸性蛋白(分子量18000KD)主要表達(dá)在細(xì)胞核內(nèi),與各種細(xì)胞周期相關(guān)的核蛋白質(zhì)相互作用,如絲裂素活化蛋白激酶的激酶(mitogen activated protein kinase kinase,MAPKK/MTK1),細(xì)胞分裂調(diào)控蛋白2(cell dicision control2,Cdc2),增殖細(xì)胞核抗原(PCNA),p21以及核心組蛋白等發(fā)生相互作用。Gadd45a基因的第三個(gè)內(nèi)含子區(qū)段,存在一個(gè)高度保守的p53結(jié)合位點(diǎn),野生型p53可以與此作用位點(diǎn)結(jié)合,促進(jìn)Gadd45a基因的轉(zhuǎn)錄表達(dá),各種影響p53因素均可導(dǎo)致Gadd45a基因啟動(dòng)子活性的下降,如cmyc鋅指蛋白ZBRK1.Gadd45α是Gadd45基因家族中唯一的p53靶基因,它在細(xì)胞的生命過程中起到重要的作用,其中包括遺傳物質(zhì)穩(wěn)定性的維持、細(xì)胞周期的調(diào)控、核苷酸剪切修復(fù)以及凋亡調(diào)控等。 造血細(xì)胞包括造血干細(xì)胞和造血祖細(xì)胞,對(duì)放射線照射非常敏感。5-10Gy的放射線照射劑量很可能導(dǎo)致小鼠造血系統(tǒng)破壞從而導(dǎo)致死亡。已知Gadd45α作為壓力刺激敏感反應(yīng)基因,Gadd45家族中的唯一p53下游靶基因,而p53作為放射線照射反應(yīng)的重要信號(hào)通路,調(diào)節(jié)細(xì)胞的增殖、DNA修復(fù)以及凋亡,從而我們通過Gadd45a基因敲除小鼠的體外骨髓造血干細(xì)胞(Haematopoietic stem cells,HSCs)單克隆培養(yǎng)、體內(nèi)競爭性移植、細(xì)胞免疫熒光等實(shí)驗(yàn)研究Gadd45a在HSC自我更新能力和損傷修復(fù)能力中的作用。 實(shí)驗(yàn)結(jié)果顯示在正常的生理水平下Gadd45a基因缺失小鼠骨髓造血干／祖細(xì)胞表型分析并無差異。全骨髓競爭性連續(xù)移植及干細(xì)胞競爭性移植實(shí)驗(yàn)顯示,Gadd45a基因缺失小鼠骨髓長期造血干細(xì)胞造血重建能力升高,而祖細(xì)胞水平功能下降。 在放射線損傷情況下,Gadd45a基因缺失小鼠骨髓造血干／祖細(xì)胞表型分析仍無差異。體外單克隆培養(yǎng)顯示,Gadd45a基因缺失小鼠骨髓長期／短期／多潛能祖細(xì)胞均抵抗低劑量放射線損傷；全骨髓移植后受體小鼠給予8.5Gy放射線照射損傷顯示,Gadd45a基因缺失HSC對(duì)放射線敏感性無影響；競爭性骨髓移植受體小鼠給予連續(xù)兩次4.5Gy放射線處理實(shí)驗(yàn)顯示,在應(yīng)激損傷條件下,Gadd45a基因缺失有利于小鼠HSC自我更新,并由凋亡減少而導(dǎo)致的造血干細(xì)胞數(shù)目增多；低劑量放射線損傷,體外檢測Gadd45a基因缺失小鼠骨髓造血干細(xì)胞凋亡無差異,增殖升高,同時(shí)低劑量放射線損傷證實(shí)Gadd45a基因缺失小鼠骨髓造血干細(xì)胞DNA損傷修復(fù)較快。無論是在正常情況下還是應(yīng)激反應(yīng)中Gadd45a基因缺失均導(dǎo)致HSC功能上升,提示Gadd45a基因在維持HSC穩(wěn)態(tài)方面起重要作用。
[Abstract]:Gadd45 is a gene for growth inhibition and DNA damage (Growth arrest and DNA damage inducible gene Gadd45) was found in Fornace, etc. in 1988, the.Gadd45 family included three members. The important role of the [2-3].Gadd45 gene family is very similar to about 57% gene homology, which is usually induced by the initiation of the DNA repair pathway after the action of the environmental damage factor.
Gadd45a protein is a small Spherular acidic protein (molecular weight 18000KD) expressed mainly in the nucleus, interacting with nuclear proteins associated with various cell cycles, such as mitogen activated protein kinase kinase, MAPKK/MTK1, cytokinesis regulated protein 2 (cell dicision control2, Cdc2), and proliferation. Nuclear antigen (PCNA), p21 and core histone have third intron segments that interact with.Gadd45a genes. There is a highly conserved p53 binding site. Wild type p53 can combine with this site to promote the transcriptional expression of the Gadd45a gene. All kinds of p53 factors can lead to the activity of the Gadd45a gene promoter. Drop, such as cmyc zinc finger protein ZBRK1.Gadd45 alpha, is the only p53 target gene in the Gadd45 gene family, which plays an important role in the cell life process, including the maintenance of the stability of the genetic material, the regulation of cell cycle, the repair of nucleotide shear and the regulation of apoptosis.
Hematopoietic cells include hematopoietic stem cells and hematopoietic progenitor cells. Radiation exposure dose of.5-10Gy, which is very sensitive to radiation exposure, is likely to cause damage to the hematopoietic system in mice and lead to death. Gadd45 alpha is known as the pressure sensitive response gene, the only p53 downstream target gene in the Gadd45 family, and p53 as a radiation exposure response The important signal pathway regulates cell proliferation, DNA repair and apoptosis, thus we study Gadd45a in the self-renewal capacity and damage repair ability of HSC through the monoclonal culture of bone marrow hematopoietic stem cells (Haematopoietic stem cells, HSCs) in Gadd45a knockout mice, in vivo competitive transplantation and cell immunofluorescence. The role.
The experimental results showed that there was no difference in the phenotype analysis of bone marrow hematopoietic stem / progenitor cells in Gadd45a gene deletion mice at normal physiological level. Competitive continuous transplantation and competitive stem cell transplantation experiments showed that the hematopoietic rebuilding ability of bone marrow stem cells in Gadd45a gene deletion mice increased and the level of progenitor cells decreased.
The phenotypic analysis of bone marrow hematopoietic stem / progenitor cells in Gadd45a gene deletion mice remained unchanged under radiation damage. In vitro monoclonal culture showed that the long / short term / multipotential progenitor cells of Gadd45a gene deletion mice were all resistant to low dose radiation injury, and the recipient mice were given 8.5Gy radiation injury after all bone marrow transplantation. Gadd45a gene deletion HSC had no effect on Radiosensitivity; competitive bone marrow transplant recipient mice given two consecutive 4.5Gy radiation treatments showed that the deletion of Gadd45a gene was beneficial to the self-renewal of HSC in mice and the increase of the number of hematopoietic stem cells induced by the decrease of apoptosis; low dose radiation. There was no difference in the apoptosis of bone marrow hematopoietic stem cells in Gadd45a gene deletion mice, and the proliferation increased. At the same time, low dose radiation damage confirmed that the DNA damage of the bone marrow hematopoietic stem cells of Gadd45a gene deletion mice was faster. The Gadd45a gene deletion in normal or stress responses led to the increase of HSC function, suggesting Gad. The d45a gene plays an important role in maintaining the homeostasis of HSC.
【學(xué)位授予單位】：北京協(xié)和醫(yī)學(xué)院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2012
【分類號(hào)】：R329.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

1 李云峰;錢海利;林晨;;Gadd45a的表達(dá)調(diào)控與功能[J];醫(yī)學(xué)分子生物學(xué)雜志;2007年05期

2 姬峻芳;吳e，

本文編號(hào)：1998524