Sodré C P, Guilherme R S, Meloni V F A, Brunoni D, Juliano Y, Andrade J A D, Belangero S I N, Christofolini D M, Kulikowski L D, Melaragno M I
Departamento de Morfologia e Genética da Universidade Federal de São Paulo, São Paulo, SP, Brasil.
Genet Mol Res. 2010 Jan 26;9(1):134-43. doi: 10.4238/vol9-1gmr707.
Ring chromosomes are often associated with abnormal phenotypes due to loss of genomic material and also because of ring instability at mitosis after sister chromatid exchange events. We investigated ring chromosome instability in six patients with ring chromosomes 4, 14, 15, and 18 by examining 48- and 72-h lymphocyte cultures at the first, second and subsequent cell divisions after bromodeoxyuridine incorporation. Although most cells from all patients showed only one monocentric ring chromosome, ring chromosome loss and secondary aberrations were observed both in 48- and 72-h lymphocyte cultures and in metaphase cells of the different cell generations. We found no clear-cut correlation between ring size and ring instability; we also did not find differences between apparently complete rings and rings with genetic material loss. The cytogenetic findings revealed secondary aberrations in all ring chromosome patients. We concluded that cells with ring chromosome instability can multiply and survive in vivo, and that they can influence the patient's phenotype.
环状染色体常因基因组物质丢失以及姐妹染色单体交换事件后有丝分裂时环状染色体的不稳定性而与异常表型相关。我们通过检测在掺入溴脱氧尿苷后的第1、第2及后续细胞分裂时培养48小时和72小时的淋巴细胞，研究了6例分别携带4号、14号、15号和18号环状染色体患者的环状染色体不稳定性。尽管所有患者的大多数细胞仅显示一条单中心环状染色体，但在48小时和72小时的淋巴细胞培养物以及不同细胞代的中期细胞中均观察到了环状染色体丢失和继发性畸变。我们未发现环状染色体大小与环状染色体不稳定性之间存在明确的相关性；我们也未发现明显完整的环状染色体与有遗传物质丢失的环状染色体之间存在差异。细胞遗传学结果显示所有环状染色体患者均有继发性畸变。我们得出结论，具有环状染色体不稳定性的细胞能够在体内增殖并存活，并且它们会影响患者的表型。
