Team:Fudan D/Intron

The counting mechanism of the telomere inspires us to control the life span of the yeast with an artificial telomere. We hope to control the life of the yeast after the splicing of telomere through several generations. The method is that insert the functional gene into telomere sequence and the splicing of telomere destroys the functional gene to achieve the aim of killing the yeast.

There are some premises for our model:

1. The telomere is over-elongated. Only the over-elongated telomere can be spliced.

2. The sequence inserted into the telomere need to be shorter than 30bp. If the inserted sequence is short enough, the separated telomere would be still recognized as one over-elongated telomere and the splicing would continue.

In our project, the functional gene is divided into two parts: 5’reporter and 3’reporter. The length of 3’reporter is shorter than 30bp. Between 5’reporter and 3’reporter, we insert a sequence of intron which is at the length of 40~50bp. The 5’reporter, 3’reporter and the intron can be transcribed at the same time. However, in the post-transcription modification, the transcription product of the intron would be spliced and the transcription product of 5’reporter and 3’reporter would be ligated and could be further translated into normal protein product.

In our model, we also divide the sequence of telomere into two parts telomere repeats Ⅰ and telomere repeats Ⅱ. We insert telomere repeats Ⅰ into the intron. In this way, only 3’reporter is really inserted into the telomere sequence. Since the length of 3’reporter is short and the cell still can recognize the overlong telomere and splice the telomere, the 3’reporter will be destroyed eventually and the functional gene cannot express normally. Therefore, the yeast cannot grow and die.

[1] Luukkonen, B. and B. Séraphin (1999). "A conditional U5 snRNA mutation affecting pre-mRNA splicing and nuclear pre-mRNA retention identifies SSD1/SRK1 as a general splicing mutant suppressor." Nucleic Acids Research 27(17): 3455-3465.