A PORTABLE REGULATORY ELEMENT DIRECTS SPECIFIC EXPRESSION OF THE CAENORHABDITIS-ELEGANS UBIQUITIN GENE UBQ-2 IN THE SOMATIC GONAD

The Caenorhabditis elegans ubq-2 gene encodes a fusion of ubiquitin an d a 52-amino-acid ribosomal protein. This single copy gene is both cis - and trans-spliced. It is expressed in all life stages of the worm an d its transcript abundance is unaffected by heat stress. Transgenic an alysis shows that expression of ubq-2 is regulated by an upstream prom oter and a downstream element. The downstream element is required for ubq-2 promoter activity in embryos and in cells of the somatic gonad, including the distal tip cells, sheath cells, spermathecal cells, and cells of the uterus. The gonad-specific activity of the downstream reg ulator is transferable to a stress gene promoter such that heat-induci ble expression of the transgene occurs in the somatic gonad. Stress-in ducible beta-galactosidase expression in the gonad does not occur in a ll life stages, but is initiated late in the second or early in the th ird larval stage, when differentiation of gonadal tissues begins. Expr ession of a beta-galactosidase fusion protein from constructs containi ng the downstream ubq-2 regulator causes abnormalities of the gonad an d embryonic lethality. Gonad abnormalities include arrested developmen t and general disorganization. These abnormalities may be related to t he overexpression of ubiquitin in the gonad. (C) 1995 Academic Press, Inc.