INHIBITION OF MYOBLAST FUSION AFTER ONE ROUND OF DNA SYNTHESIS IN 5-BROMODEOXYURIDINE
INHIBITION OF MYOBLAST FUSION AFTER ONE ROUND OF DNA SYNTHESIS IN 5-BROMODEOXYURIDINE
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DOI：
10.1083/jcb.44.1.134
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发表时间：
1970-01-01
影响因子：
7.8
通讯作者：
HOLTZER, H
中科院分区：
文献类型：
--
作者：
BISCHOFF, R;HOLTZER, H
胸苷类似物5-溴脱氧尿苷（BUdR）对生长和分裂所需的组织特异性产物和分子的合成具有不同的影响。在BUdR中培养的增殖性肌源性细胞不能融合，也不能启动收缩性蛋白丝的合成。相反，BUdR对细胞活力和生殖完整性的影响很小。低浓度的BUdR导致细胞数量相对于对照增加;较高浓度具有细胞毒性。在类似物中生长至少10代细胞后，对肌生成的抑制是可逆的。不合成DNA的细胞，如有丝分裂后的成肌细胞和肌管，不受BUdR的影响。通过在融合前首先在5-氟脱氧尿苷（FUdR）中孵育肌原性细胞以阻断DNA合成并收集合成前阶段的细胞来完成BUdR的掺入用于一轮DNA合成。然后，通过用BUdR或BUdR加胸苷（TdR）绕过FUdR阻断，使细胞合成正常DNA或BU-DNA一个S期。在FUdR中继续培养，以防止通过进一步分裂稀释掺入的类似物。3天后，FUdR-BUdR系列的培养物显示出典型的BUdR效应;细胞过度扁平化，形成很少的多核肌管。对照培养物中的细胞形态正常，存在多核肌管。这些结果在另一个实验中得到证实，其中将BUdR-3 H加入到正在形成肌管的2天培养物中。胸苷-3H标记细胞的融合在前一个S期后8小时开始。相反，细胞纳入BUdR-3 H一个S期不融合与正常肌管。
The thymidine analogue 5-bromodeoxyuridine (BUdR) has a differential effect on the synthesis of tissue-specific products and molecules required for growth and division. Proliferating myogenic cells cultured in BUdR fail to fuse and fail to initiate the synthesis of contractile protein filaments. Conversely, BUdR has but a minor effect on cell viability and reproductive integrity. Low concentrations of BUdR result in an enhancement of cell number relative to the controls; higher concentrations are cytotoxic. Suppression of myogenesis is reversible after at least 10 cell generations of growth in the analogue. Cells that do not synthesize DNA, such as postmitotic myoblasts and myotubes, are not affected by BUdR. Incorporation of BUdR for one round of DNA synthesis was accomplished by first incubating myogenic cells, prior to fusion, in 5-fluorodeoxyuridine (FUdR) to block DNA synthesis and collect cells in the presynthetic phase. The cells were then allowed to synthesize either normal DNA or BU-DNA for one S period by circumventing the FUdR block with BUdR or BUdR plus thymidine (TdR). The cultures were continued in FUdR to prevent dilution of the incorporated analogue by further division. After 3 days, the cultures from the FUdR-BUdR series showed the typical BUdR effect; the cells were excessively flattened and few multinucleated myotubes formed. Cells in the control cultures were of normal morphology, and multinucleated myotubes were present. These results were confirmed in another experiment in which BUdR-3H was added to 2-day cultures in which myotubes were forming. Fusion of thymidine-3H-labeled cells begins at 8 hr after the preceding S phase. In contrast, cells which incorporate BUdR-3H for one S period do not fuse with normal myotubes.