Table 3. Patterns of mutation in Vλ of Brca1-/-, XRCC3-/- and Brca1-rescued DT40.
| A Sequence changes in Vλ, without and without selection for surface IgM phenotype (all events pooled) | ||||||
|---|---|---|---|---|---|---|
| Genotypea | Gene conversion
(% of total events) |
Non-templated point mutation
(% of total events) |
Gene conversion: point mutation ratio | Insertion/deletion/duplication
(% of total events) |
Ambiguous
(% of total events) |
Total events
(# of sequenced clones) |
| Brca1-/- “complete” clone 8 | 11
(5) |
166
(71) |
6:94 |
28
(12) |
29
(12) |
234
(548) |
| XRCC3-/- | 1
(12) |
139
(59) |
1:99 |
15
(7) |
21
(21) |
176
(277) |
| Brca1-/- “partial” | 0 | 11
(58) |
0:100 | 3
(16) |
5
(26) |
19
(68) |
| Brca1-/r (Brca1 knock-in rescue, clone F10) | 6
(22) |
12
(44) |
33:67 | 3
(11) |
6
(22) |
27
(147) |
| B Non-templated point mutation frequencies | ||||||
| Genotype | IgM- sorted | Not sorted | ||||
| Point mutations/total sequenced | Mutation frequencyb | Point mutations/total sequenced | Mutation frequencyb | |||
| Brca1-/- “complete” clone 8 | 132/337 | 0.92 x 10-3 | 32/211 | 0.36 x 10-3 | ||
| XRCC3-/- | 110/136 | 1.9 x 10-3 | 41/141 | 0.68 x 10-3 | ||
Brca1-/- “partial” is an independent clone with homozygous deficiency for Brca1, generated in the DT40 parent, with the same targeting vectors used to generate the Brca1-deficient DT40 cre derivatives. No Brca1 protein is apparent in this line. The Brca1-/- “complete,” clone 8, line has a more extensive deletion of the Brca1 locus, and also makes no detectable Brca1 protein. Numbers in table are raw numbers of each class (with all duplicated mutations from the same clone excluded to avoid resampling of the same mutations in a clonal lineage) followed in brackets by the percentage of the total in that class.
Calculated as the number of point mutations per total basepairs sequenced (total clones sequenced times 427 – the length of Vλ analyzed)