Alpha-neurotoxin gene expression in Naja sputatrix: identification of a silencer element in the promoter region.
Alpha-neurotoxin (alpha-NTX) from the venom of cobra, Naja sputatrix, is a highly lethal post-synaptic toxin that is responsible for the lethality caused by the venom. However, this toxin is found at low levels (3%) in the crude venom. The expression of its gene is determined by a promoter which is 90% similar to the promoter of another three-fingered toxin, cardiotoxin (CTX), which is produced in large amounts (60%) in the same venom. Functional analysis of the NTX-2 gene promoter demonstrated the presence of a silencer element of 24 nucleotides (nt -678 to -655) at its 5(') flanking region. This element has been found to play a major role in the down-regulation of NTX-2 gene expression. A point mutation on this silencer appears to attenuate its repressive property in CTX-2 gene.
Department of Biochemistry, Faculty of Medicine, National University of Singapore, Singapore.
Donghui
D
Ma
Arunmozhiarasi
A
Armugam
Kandiah
K
Jeyaseelan
D000818:Animals; D001483:Base Sequence; D004179:Cobra Cardiotoxin Proteins / Q000235:genetics; D003039:Cobra Neurotoxin Proteins / Q000235:genetics*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004546:Elapid Venoms / Q000235:genetics; D017815:Elapidae / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D020868:Gene Silencing; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid
D004179:Cobra Cardiotoxin Proteins; D003039:Cobra Neurotoxin Proteins; D004546:Elapid Venoms; D012097:Repressor Proteins; C025154:alpha-cobratoxin; D004247:DNA