Table 1.
Chromosomal instability in NHEJ-deficient fibroblasts
| Events | Genotypes of MEFs
|
||||||
|---|---|---|---|---|---|---|---|
| WT | Lig4−/−‡ | Lig4−/−p53−/− | p53−/− | Ku70−/−‡ | DNA-PKcs−/−‡ | NHEJ mutants combined† | |
| Metaphases karyotyped | 27 | 14 | 30 | 22 | 16 | 18 | 48 |
| Fragmented chromosomes & chromatids | 0 | 4 | 7 | 0 | 6 | 3 | 13 |
| Detached centromeres | 0 | 4 | 13 | 0 | 1 | 0 | 5 |
| Translocations | 0 | 2 | 5 | 0 | 1 | 0 | 3 |
| Robertsonian translocations (fusions) | 0 | 1 | 4 | 0 | 0 | 0 | 1 |
| Metaphases with structural abnormality,* % | 0 | 64 | 66 | 0 | 44 | 17 | 41 |
The numbers to the right of the categories of events are the total events of that type. Some metaphases had more than one event of a particular type and others a mixture of types of events. Two embryos each for wild type (WT), Lig4−/−, and Lig4−/− p53−/− were analyzed, with duplicates yielding similar results. One each of the remaining genotypes were analyzed.
*
The percentage of metaphases with any structural abnormality. Aneuploidy was not considered because all genotypes of midpassage MEFs tend to become near tetraploid.
†
Sum of events arising in the three NHEJ mutant cell lines (denoted by ‡).