Worm Breeder's Gazette 9(3): 22
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 have cloned the tra-2 gene by Tc1 tagging. The tra-2 gene product is thought to regulate the fem genes (or their products) to allow female development in both soma and germ line of XX animals (Hodgkin et al.,1985,CSHSQB,50,585-593). To isolate Tc1 insertions into tra-2, we selected for intragenic revertants of the tra-2(gf) allele q122. We backcrossed q122 (a gain-of-function allele of tra-2 that was induced by EMS on a Bristol chromosome) and a closely linked marker, e120, into two strains in which Tc1 actively transposes (TR403 or EM1002). Because XX animals heterozygous for q122 develop as females and XO animals develop as males, it is possible to construct male/female mating strains. Large populations of stable male/female strains (q122 e120/ mnCl in TR403 or EM1002) were grown on Petri plates to permit mating. Five spontaneous recessive tra-2 alleles located in cis to q122 were isolated by shifting these animals to liquid culture to prevent mating and to select for self-fertility. Two of these alleles, q149 and q150, were backcrossed several times against N2. In addition, recombinants between each of these tra-2 alleles and linked markers on both sides of tra-2 were isolated to eliminate Tc1s which are not closely linked to tra-2. A radioactively labelled Tc1 probe was used to hybridize N2 DNA, q122 e120/mnCl (in Bristol) DNA, and DNAs isolated from a strain carrying the recombined q149 or q150 chromosome in Southern blots. A single novel 7.0kb BglII fragment was detected in q150 DNA. The fragment carrying this novel Tc1 was cloned, and a unique sequence flanking the q150 Tc1 insertion was subcloned to probe DNAs from other spontaneous tra-2 alleles. Hybridization with the unique probe showed that q149 contains a short deletion and that sc146, a spontaneous tra-2 allele isolated in TR679 and kindly sent to us by Corrine Basch and Bob Edgar, contains a rearrangement. Interestingly, this TR679 derived spontaneous allele is not a Tc1 insertion. The same probe was then used to isolate 30kb of DNA in the region of tra-2 from a C. library provided by Claudia Cummins and Phil Anderson. We are currently mapping the tra-2 gene more precisely within this 30kb region and attempting to identify the tra-2 transcript.