TGF-beta receptor levels regulate the specificity of signaling pathway activation and biological effects of TGF-beta.

TGF-beta is a pluripotent cytokine that mediates its effects through a receptor composed of TGF-beta receptor type II (TGFBR2) and type I (TGFBR1). The TGF-beta receptor can regulate Smad and nonSmad signaling pathways, which then ultimately dictate TGF-beta's biological effects. We postulated that control of the level of TGFBR2 is a mechanism for regulating the specificity of TGF-beta signaling pathway activation and TGF-beta's biological effects.

Distribution and diversity of geminiviruses in trinidad and tobago.

ABSTRACT Seven crop and eight weed species from 12 agricultural locations in Trinidad and Tobago were assayed for the presence of whitefly-transmitted geminiviruses (WTGs) by using dot blot hybridization and polymerase chain reaction (PCR) amplification of the N-terminal coat protein sequence with degenerate primers. The amplified fragments were cloned and analyzed by restriction enzyme digestion to determine fragment length polymorphism among the cloned fragments. Representative clones were then sequenced and subjected to phylogenetic analysis to determine the sequence similarity to known WTGs.

Inducible control of transgene expression with ecdysone receptor: gene switches with high sensitivity, robust expression, and reduced size.

The ecdysone receptor (EcR)-based gene regulation system is a tool for controlling gene expression. To improve the sensitivity of this system, we evaluated many two-hybrid format synthetic gene constructs in which the GAL4 DNA binding domain was fused to the ligand binding domain of the Choristoneura fumiferana EcR mutant V390I/Y410E (GEvy), and various activation domains--VP16, p53, p65, or E2F-i--were fused to the EF domains of chimeric human RXR. These gene switches were assayed in NIH3T3 cells, HEK293 cells, and in mouse quadriceps in the presence of the nonsteroidal inducer RG-115819 or GS-E.

Chemically regulated gene expression in plants.

Chemically inducible systems that activate or inactivate gene expression have many potential applications in the determination of gene function and in plant biotechnology. The precise timing and control of gene expression are important aspects of chemically inducible systems. Several systems have been developed and used to analyze gene function, marker-free plant transformation, site-specific DNA excision, activation tagging, conditional genetic complementation, and restoration of male fertility.