 |
|
Figure 4
Transcription repression and telomere proximity. (A) Physical map of the ble–promoter–neo cassette and locations of four integration sites (vertical arrows) in the 'silent' vsg221 ES. The exogenous promoter and the endogenous ES promoter are indicated by horizontal arrows. (B) A Northern blot was hybridized with the probes indicated to the left of each panel. The position of integration (relative to the vsg221 start codon) in each clone, in kbp, is indicated. For the inserted rRNA promoter (R) results are shown for two independent bloodstream-form (BF) clones and one procyclic form (PF) derivative at each integration site. Only one clone was derived for each of the two insertion sites of the ES promoter (E). Cells with a cassette integrated in an active ES are shown as a positive control (active ES). (C) Bloodstream-form neo and vsg221 signals were quantified by phosphorimager analysis. neo signals were normalized against clones with the same cassettes integrated at each position into an active ES (see text). The numbers above each bar represent the number of independent clones in each data set and error bars indicate standard deviation. Symbols are as in (B).
|
|
|
|
previous
| next 
