Worm Breeder's Gazette 13(3): 35 (June 1, 1994)

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.

mab-3 YAC rescue

David Zarkower, Mario de Bono, Jonathan Hodgkin

Figure 1

MRC Laboratory of Molecular Biology, Cambridge, England

The mab-3 gene is required for at least two aspects of male development. XO animals mutant in mab-3 express abundant yolk protein in the intestine and fail to execute normal V ray lineages in the tail (Shen and Hodgkin, Cell 54:1019, 1988); XX animals are apparently unaffected. Both phenotypes are epistatic to tra-1 (lf),making mab-3 a good candidate to be regulated by tra-1 .

We are trying to clone mab-3 .The gene lies about 0.1mu left of unc-4 on LGII. Michael Shen(1) identified two Bergerac polymorphisms, eP43 and eP44 ,close to mab-3 and established a cosmid contig of about 480kb containing the region. Caroline Shamu(2) further refined the position of mab-3 by identifying the endpoints of several chromosomal deficiencies in the region. mab-3 lies between the left endpoints of mnDf26 and mnDf57 (see figure below). Thus mab-3 probably is near the left end of the eP43 contig or on the adjacent YAC bridge. We tried unsuccessfully to rescue a mab-3 mutant by injection of relevant cosmid clones, either singly or pairwise. This suggested either that mab-3 lies on the YAC bridge or that it is a difficult gene to rescue. To resolve this, we injected mab-3 ( mu15 ); him-5 ( e1490 )XX animals (gift of Deborah Cowing) with Y53C12 and rol-6 DNA. One of two transmitting lines examined showed significant rescue of V rays and yolk expression, with some animals making all 12 V rays. This result suggests that mab-3 lies on the YAC bridge. Caroline Shamu tried a phage walk from the right side of the bridge using YAC minilibraries and was unable to get significant extension of the contig. We are now trying to walk from the left side and to make smaller YAC derivatives.

Literature Cited:

1 M. Shen, PhD thesis, Cambridge University, 1988.

2 C. Shamu, MPhil thesis, Cambridge University, 1989.

Figure 1