Multiple Structural Aberrations Research Articles

Multiple structural aberrations and physical mapping of rye chromosome 2R introgressed into wheat

Multiple structural aberrations produced by chromosome breakage and reunion not only provide new germplasm for enriching genetic diversity but are also helpful for physical mapping of alien chromosomes introgressed into wheat. In this study, mass structural aberrations of rye chromosome 2R were induced by means of spontaneous breakage and reunion, gametocidal chromosome action and irradiation. A total of 88 chromosome 2R aberrations were identified in 65 plants. From the self-pollinated progenies of plants carrying these aberrations, 19 stable lines with different segments of chromosome 2R which included seven whole arm, six small segmental and three large segmental translocations, one deletion and two ditelosomic additions, were subsequently identified and characterized using cytogenetic and molecular markers. Based on these lines, 88 markers specific for chromosome 2R were physically mapped to 13 different blocks of 2R with three in arm 2RS and 10 in arm 2RL. The powdery mildew resistance gene PmJZHM2RL was located to a region corresponding to the block 2RL-7. A total of eighteen 2R-specific EST markers were located in the same block where ten were derived from genes that were up-regulated during powdery mildew infection. Potential use of these stable aberrations and the colinearity of chromosome 2R with corresponding chromosomes in the other model monocot species were discussed.

Establishment of a novel Chinese metastatic melanoma cell line showing the new cytogenetic and biological properties.

Malignant melanoma remains the most life-threatening skin cancer to date. What makes it worse is the incidence keeps increasing worldwide, including in China. Notably, clinical studies revealed the distinct features in the Chinese population differing from those in Caucasians, which give hints to variant mechanisms underlying. Therefore, it is of great importance to generate a cell line with similar background for melanoma research in Chinese even Asian patients. However, most melanoma cell lines in use are derived from Caucasians, thus, we established one novel metastatic melanoma cell line, FLFMM-34, derived from a Han Chinese woman. The cell line showed positive for S100, HMB45, vimentin and melan-A. Chromosome analysis revealed multiple structural aberrations. Gene-mutation analysis identified that FLFMM-34 cells had BRAF(V600E) mutation and deletions of exon 2 and 3 in p16/CDKN2A. Importantly, two novel mutations including TP53(P33R) and TP53(R142H) have been detected. RT-PCR results showed that FLFMM-34 cells expressed a higher mRNA level of cyclinD1 than three other melanoma cell lines, WM793B, 1205Lu and A2058. In addition, in vivo mice model demonstrated that the cells could be transplanted into the subcutis of nude mice and produced tumors associated with lymphoid node metastases. In conclusion, these data indicate that FLFMM-34 cell line can be employed as a suitable model for melanoma research in Chinese Han population.

Establishment and Characterization of a Cell Line (CUMC-3) Derived from a Human Squamous Carcinoma of the Uterine Cervix

A new cell line, CUMC-3, has been derived from an invasive nonkeratinizing squamous cell carcinoma of the uterine cervix in a 32-year-old patient. It has been maintained in long-term culture for 59 months, and passaged over 310 times. Monolayer-cultured cells were polygonal in shape, showing a pavement-like arrangement and a tendency to pile up without contact inhibition. The epithelial nature of the cultured CUMC-3 cells was also confirmed by transmission electron microscopy which demonstrated the presence of desmosomes and tonofilaments. The cells were highly tumorigenic in nude mice and the transplanted tumors were poorly differentiated squamous carcinoma which closely resembled the original tumor. Cultured cells obtained from the CUMC-3-derived nude mouse tumor, CUMC-3N, also were studied for its characterization. Repeated chromosome analysis revealed a stable clone with the modal chromosome number of 78. The metaphase of this cell line had multiple structural aberrations of chromosomes 1, 3, 8, 10, 11, 20, and X and showed several markers of unknown origin. The results of isozyme analyses were distinct from the HeLa cell line. The identical genetic signature was demonstrated both in CUMC-3 and in CUMC-3N cells. Cultured CUMC-3 cells produced human chorionic gonadotropin β-subunit and tumor antigen of squamous cell carcinoma (TA-4). Cytosol estrogen receptors were found in this cell line but progesterone receptors were not measured. HLA typing of CUMC-3 cells indicated the presence of DR4, DR8, DQw3, and DQw6. The result of oncogene analysis using Southern blotting technique revealed no amplification of oncogene c-myc. Analysis of the DNA samples extracted from the CUMC-3 cells showed the presence of human papillomavirus type 16 DNA. Using the single-strand conformation polymorphism technique, we have screened CUMC-3 cells for p53 mutation in exons 4 to 9. No mobility shift was observed in this cell line. This cell line may be useful in studying the in vitro and in vivo properties of human cervical carcinoma.

Isochromosomes i(8q) or i(9q) in three adenocarcinomas of the lung

We have cytogenetically analyzed three primary adenocarcinomas of the lung. All tumors had chromosome numbers in the triploid region. The multiple structural aberrations included rearrangements of 3p, in two cases affecting the segment 3p14–23, where deletions are characteristically found in small cell lung carcinomas. Isochromosomes for 8q were present in two tumors and i(9q) in one tumor. In the few previously reported cytogenetic analyses of pulmonary adenocarcinomas, all of which examined metastases or cell lines, i(8q) was found in one case and i(9q) in two cases. These isochromosomes, therefore, represent previously unrecognized nonrandom changes in adenocarcinomas of the lung, and might constitute primary aberrations in this tumor type.