Receptor-evoked Cl- current in Xenopus oocytes is mediated through a beta-type phospholipase C. Cloning of a new form of the enzyme.


Journal Article

Xenopus oocytes exhibit a receptor-evoked Cl- current that is mediated through the activation of phospholipase C (PLC) and release of intracellular Ca2+. The identity of PLC(s) mediating this effect is unknown. We have cloned cDNAs encoding a new form of PLC-beta from a Xenopus oocyte cDNA library. The Xenopus PLC-beta has substantial (33-64%) homology with mammalian beta 1, beta 2, beta 3, and beta 4 phospholipase C and is closest to PLC-beta 3, with 64% identity and 80% similarity. Injection of antisense oligonucleotides to a specific region of Xenopus PLC-beta results in degradation of its mRNA and significantly reduces Cl- currents evoked by both endogenous angiotensin receptors and expressed mammalian alpha 1b-adrenergic receptors and M1-muscarinic receptors as compared to responses in sense oligonucleotide-injected oocytes. Inhibition of the M1-muscarinic response by antisense oligonucleotides was nonadditive with pertussis toxin inhibition. PLC antisense oligonucleotide-injected oocytes show Cl- current responses to IP3 that are indistinguishable from sense oligonucleotide-injected oocytes. Since the receptor responses are pertussis toxin-sensitive, we conclude that we have isolated a new form of PLC-beta involved in the pertussis toxin-sensitive receptor stimulation of the Ca2+ activated Cl- current in Xenopus oocytes.

Full Text

Cited Authors

  • Ma, HW; Blitzer, RD; Healy, EC; Premont, RT; Landau, EM; Iyengar, R

Published Date

  • September 1, 1993

Published In

Volume / Issue

  • 268 / 27

Start / End Page

  • 19915 - 19918

PubMed ID

  • 8397190

Pubmed Central ID

  • 8397190

Electronic International Standard Serial Number (EISSN)

  • 1083-351X

International Standard Serial Number (ISSN)

  • 0021-9258


  • eng