Molecular cloning and characterization of crustacean type-one dopamine receptors: D-1 alpha Pan and D-1 beta Pan
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY
Authors: Clark, MC; Baro, DJ
Abstract
Dopamine (DA) differentially modulates identified neurons in the crustacean stomatogastric nervous system (STNS). While the electrophysiological actions of DA have been well characterized, little is known about the dopaminergic transduction cascades operating in this system. As a first step toward illuminating the molecular underpinnings of dopaminergic signal transduction in the crustacean STNS, we have cloned and characterized two type-one DA receptors (DARs) from the spiny lobster (Panulirus interruptus): D-1 alpha Pan and D-1 beta Pan. We found that the structure and function of these arthropod DARs are well conserved across species. Using a heterologous expression system, we determined that DA, but not serotonin, octopamine, tyramine or histamine activates these receptors. When stably expressed in HEK cells, the D-1 alpha Pan receptor couples with Gs, and DA elicits an increase in [CAMP]. The D-1 beta Pan receptor responds to DA with a net increase in [CAMP] that is mediated by Gs and Gz. (C) 2005 Elsevier Inc. All rights reserved.
darR and darS are regulatory genes that modulate 2-hexyl, 5-propyl resorcinol transcription in Pseudomonas chlororaphis PCL1606
MICROBIOLOGY-SGM
Authors: Calderon, Claudia E.; Carrion, Victor J.; de Vicente, Antonio; Cazorla, Francisco M.
Abstract
Pseudomonas chlororaphis PCL1606 synthesizes the antifungal antibiotic 2-hexyl, 5-propyl resorcinol (HPR), which is crucial for the biocontrol of fungal soil-borne pathogens. The genetic basis for HPR production lies in the dar genes, which are directly involved in the biosynthesis of HPR. In the present study, we elucidated the genetic features of the dar genes. Reverse transcription PCR experiments revealed an independent organization of the dar genes, except for darBC, which was transcribed as a polycistronic mRNA. In silico analysis of each gene revealed putative promoters and terminator sequences, validating the proposed gene arrangement. Moreover, experiments utilizing 5' rapid amplification of cDNA ends were used to determine the transcriptional initiation sites for the darA, darBC, darS and darR gene promoters, and subsequently to confirm the functionality of these regions. The results of quantitative real-time PCR experiments indicated that biosynthetic dar genes were not only modulated through the global regulator gacS, but also through darS and darR. The interplay between darS and darR revealed transcriptional cross-inhibition. However, these results also showed that other regulatory parameters play a role in HPR production, such as the environmental conditions and additional regulatory genes.