Mutant expression of male copulatory bursa surface markers in Caenorhabditis elegans.

In a search for molecular markers of male tail morphogenesis in C. elegans, we have detected two surface markers that are specifically observed in the copulatory bursa of adult males and the vulva of adult hermaphrodites. These markers are defined by binding of a monoclonal antibody (Ab117) and the lectin wheat germ agglutinin (WGA) to live intact animals. Expression of these markers is dependent on sex, stage and anterior-posterior position in the animal. Four of ten mutants with specific defects in bursal development show altered expression of one or both markers. Because the WGA marker can be expressed in intersexual animals with very little bursal development, posterior surface expression of this marker can serve as an indication of subtle masculinization of hermaphrodites. The timing of expression of these markers is not affected by heterochronic mutations that cause larval animals to express adult cuticles or adult animals to express larval cuticles, indicating that marker expression can be uncoupled from general cuticle development. Mutant lin-22 males, which have an anterior-to-posterior transformation of cell fates in the lateral hypodermis, ectopically express both markers in a manner consistent with a 'posteriorization' of positional information in these animals. These markers should be useful for the isolation and characterization of mutants defective in bursal and vulval development, sex determination and expression of anterior-posterior positional information.