小鼠骨髓瘤细胞与同种和异种网织红细胞杂交后的杂种子代的细胞遗传学分析

本研究用小鼠骨髓瘤BW胸腺淋巴肉瘤,分别与富含血红素和珠蛋白mRNA的正常兔网织红细胞或小鼠网织红细胞杂交,分别取子代杂种细胞第1、2、4、5、6、7、9、16、20代,进行染色体数目和结构畸变的分析。亲代BW计数206个中期细胞,各代杂种共计数1592个中期细胞。结果发现,杂种1、2、4代细胞染色体数目,包括标记染色体明显减少,亚众数含40～49条染色体的细胞明显增多,有10%细胞甚至降至20～29条。但以后各代细胞的染色体数目又趋于回升,并接近亲代染色体数量水平。数量在20～29范围内的细胞已极少存活。杂交细胞各代均保留有特大标记染色体,但染色体畸变率则明显低于亲代细胞,有显著的统计学差异(P<0.001)。上述染色体数量和畸变率的明显改变,与杂交细胞呈现的恶性生长受到抑制互为一致,表明胞质因子对杂交细胞的分裂活动及分裂过程中的染色体形成产生了影响,并进一步为胞质因子可引致染色体改变和丢失提供了证据。

KARYOTYPE ANALYSIS OF CYBRID CELLS FUSED BETWEEN MOUSE MYELOMA CELL LINE BW AND MOUSE OR RABBIT RETICULOCYTES

Cybrid cells derived from the fusion of mouse myeloma cells (BW thymolymphosarcoma) and anucleated but rich in globin mRNA, normal rabbit and mouse reticulocytes respectively were cultured and selected in HAT selected medium. Chromosomal numbers and structure aberrations of filial generation cells 1,2,4,5 and 6, 7,9,16,20 are analysed. 206 metaphase cells from parental BW and 1592 metaphase cells from various filial generations are counted. The results showed that chromosomal numbers of 1,2,4 filial generation were obviously decreased, in which about 10% of cybrid cells with chromosome number dropped to 20-29 level, however this part of cybrid cells were hardly survived during continuous cultivation, and the chromosome numbers in the cybrid cells of later filial generations were increased to a level close to that of BW parent cells. The chromosomal aberration frequency in cybrid cells of various generations was also decreased as compared with the WB-thymophomal cells, the differences between them being statistically significant (p<0.001). Both the parent myeloma cells and the cybrid cells of filial generations maintained their trisomy -8, -9, -13 and the largest marker chromosome. Based on banding analysed, we found that the largest marker chromosome might be derived from the breakage and translocation of the No. 3 and X chromosomes of the BW myeloma cells. The relation between the decrease of chromosome number and chromosomal aberration rate of cybrid cell generations and the regulatory effect of cytoplasmic factors in reticulocytes was discussed.