Note for Increased Ratio of Targeted to Random Integration after Transfection of Chicken B Cell Lines

Note for: Increased Ratio of Targeted to Random Integration after Transfection of Chicken B Cell Lines

(doi: 10.1016/0092-8674(91)90581-I)

Viral infection cell line;

1.avian leukosis virus-induced chicken B cell line

2. 4 cell line were used to check the targeted integration but only B-cell had the highest rate of targeted integration compare to non-B cell

Factor contributes to the ratio of targeted integration/random (mammalian);

1.length of homology - the longer is better

2.transcription rate of target loci

normal rate - 1/100-1/10,000 (in mammalian genome)

There were the attempts to increase the rate of targeted in mammalian - modified the input DNA or synchronize the cells

Main point of this paper;

1.Higher ratio of targeted integration in DT40 vs mammalian

2.Compare with other types of chicken cell lines, B-cell lines had a higher frequency of targeted integration.

3.Higher ratio of targeted integration in DT40 does not rely on the transcriptional activity.

Ovalbumin is not transcribed in chicken B cell bc of this gene is state-specific by which it expresses in oviduct cell upon estrogen activation.

Reason to pick beta-actin promoter for constructing the expression cassette is this corresponding mRNA is normally abundant by most of the cell lines.

My observation is

1.can be applied to other organisms

2.highly transcribed within diverse kinds of host

The author explained that the reason behind the high ratio, it may be related to diversification of the Ig loci by gene conversion --> there might be the enzymes which used in the diversification process but also facilitate the targeted integration.

Future study;

Study in mechanistic on targeted integration in DT40 cell line would be applied to understand the efficiency of targeted integration in other organisms.