Worm Breeder's Gazette 11(3): 57
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
We are interested in identifying the genetic factor which is responsible for transposition and excision of Tc1 in the germ line. Ikue Mori mapped several 'mutators': loci that are responsible for germ line activation of Tc1 and that may be mobile themselves ( Genetics, 120, 397-407). We are fine mapping one of the mutators. mut-5 (which was mapped by Ikue Mori on chromosome II between dpy-10 and rol-1).A three factor cross was done to map mut-5 (in RW7474, obtained from Ikue Mori) in the interval dpy-10 unc-4. The results were as follows: [See Figure 1] We used one of the Unc-4 Mut+ recombinants to check if in this strain the mutator was indeed linked to unc-4 (less then 0.5 m.u. away), and results show that this is indeed the case. Since this cross indicated that mut-5 maps closer to dpy-10 than to unc-4 we did a three factor cross with a dpy-10 vab-9 strain. Among 26 selected Vab-9 recombinants 5 were found to be Mut+d 21 Mut-. This indicates that mut-5 is to the left of but quite close to vab-9. We distinguish two possibilities: 1. mut-5 is a Tc1 that is transcribed in the germline as the result of its surrounding sequences (e.g. a nearby enhancer). 2. mut-5 is a gene or another transposon, the product of which is needed for transposition of Tc1. We will screen our recombinants from the dpy-10 ctor cross for polymorphisms that cosegregate with mut-5. Assuming that the mutator is a mobile element itself (Tc1 or another element) we should be able to recognize it in Southern blots using as probes cosmids that map to the left of vab-9. Once a polymorphism is identified that cosegregates with mut-5 we will try to clone it from a Mut-5+ strain. [See Figure 2]
