Molecular cloning of genes encoding toxins in the venom of Naja naja sputatrix

Jeyaseelan, Kandiah; Armugam, Arunmozhiarasi; Earnest, Linda; Yeo, Mei-Shi; Lachumanan, Ramkumar; Tan, Nget-Hong; Gopalakrishnakone, P.; Tan, C.H.

doi:10.1016/0041-0101(95)98357-2

Cited by 3 publications

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“…Variations at a similar location on exon 2 were also observed among the five other N. n. sputatrix CTX gene sequences. This region does in fact correspond to the ‘hyper‐variable segment’ reported earlier in CTX cDNAs [12].…”

Section: Discussionsupporting

confidence: 71%

“…Although the presence of isoforms of the cardiotoxin molecule in a single venom source and multiple types of cardiotoxin cDNA in a venom gland had been reported [12, 21], this is the first report that traces the source of all these variations to the genome of N. n. sputatrix .…”

Section: Discussionmentioning

confidence: 84%

“…PCR amplification of N. n. sputatrix genomic DNA was carried out using C1 and C2 as sense and antisense primers respectively. These primers were designed based on the highly conserved region of the CTX cDNAs [12](Fig. 1A).…”

Section: Resultsmentioning

confidence: 99%

“…The accelerated evolution model fits the evolutionary mechanism of the CTX gene isoforms, where the introns and some stretches of exons are highly conserved with variations limited to specific stretches in the exons. In return, these isoforms encode cardiotoxins which have been shown to possess variable physiological activities [12]and could be important in manifestation of diverse pharmacological roles. The other region of variability seen on the CTX gene is located on a very small stretch on exon 3 (nucleotides 2577–2583).…”

Section: Discussionmentioning

confidence: 99%

“…The kit employs two thermostable DNA polymerases, the first is Tth DNA polymerase which acts as primary polymerase, and the second DNA polymerase, Vent, provides 3′‐5′ proofreading activity. Primers used were designed based on the highly conserved regions in the structural gene of N. n. sputatrix cardiotoxin cDNAs [12]as shown in Fig. 1 A.…”

Section: Methodsmentioning

confidence: 99%

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Structure and organization of the cardiotoxin genes in Naja naja sputatrix¹

et al. 1998

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We report the genomic structure, organization and the presence of multiple isoforms of the gene encoding cardiotoxins (CTX) of Naja naja sputatrix. The cardiotoxin gene consists of six CTX isoforms, each (2.2 kb) having three exons and two introns. Two possible transcription initiation sites as well as consensus TATA boxes and transcription factor binding motifs, AP-2, NFIL-6/C/EBP, NF-kappaB and PuF have been identified in the 5'-region of the gene. The CTX gene isoforms show nucleotide variations at specific segments in exon 2 and exon 3, which correspond to the functional domains in the three-finger loop structure of the cardiotoxin molecule. The diverse functions of cardiotoxins together with our findings suggest that the cardiotoxin gene isoforms may have evolved under adaptive pressure through a positive Darwinian selection process.

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Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Structure and organization of the cardiotoxin genes in Naja naja sputatrix¹

et al. 1998

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Molecular cloning, characterization and evolution of the gene encoding a new group of short‐chain α‐neurotoxins in an Australian elapid, Pseudonaja textilis

2000

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The structure and organization of five genes responsible for the synthesis of six isoforms of short-chain K K-neurotoxins in Pseudonaja textilis venom are reported in this paper. This also forms the first report which describes the synthesis of two neurotoxin mRNA variants from one of these genes (Pt-sntx1) as a result of alternative splicing. Each gene consists of three exons which are separated by two introns and each has a functional promoter. The promoter activity was confirmed by both CAT assay and Real-Time PCR. A transcription initiation site, two putative TATA boxes, one CCAAT box and the transcription factor binding consensus sites for AP-1, GATA-2, c/EBPb were identified in the 5P P non-coding region of each gene. Phylogenetic analysis showed that these five genes from P. textilis constituted a distinct group which has evolved by gene duplication followed by accelerated evolution from an ancestral gene.z 2000 Federation of European Biochemical Societies.

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Structurally conserved α‐neurotoxin genes encode functionally diverse proteins in the venom of Naja sputatrix¹

et al. 2003

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The structure and organization of the genes encoding the long-chain neurotoxins and four other isoforms of weak neurotoxins in the venom of Naja sputatrix are reported. The genes contained three exons interrupted by two introns, a structure similar to other members of the three-¢nger toxin family. The proteins encoded by these genes, however, show varied af¢nity towards nicotinic acetylcholine receptors. Phylogenetic analysis of these genes showed that the weak neurotoxin gene is con¢ned to a distinct group. We also observe that speci¢c mutations of the gene provide the diversity in function in these toxins while maintaining a common structural sca¡old. This forms the ¢rst report where the molecular basis of evolution of postsynaptic neurotoxins from an ancestral gene can be demonstrated using the same species of snake.

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Molecular cloning of genes encoding toxins in the venom of Naja naja sputatrix

Cited by 3 publications

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Structure and organization of the cardiotoxin genes in Naja naja sputatrix¹

Structure and organization of the cardiotoxin genes in Naja naja sputatrix¹

Molecular cloning, characterization and evolution of the gene encoding a new group of short‐chain α‐neurotoxins in an Australian elapid, Pseudonaja textilis

Structurally conserved α‐neurotoxin genes encode functionally diverse proteins in the venom of Naja sputatrix¹

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Molecular cloning of genes encoding toxins in the venom of Naja naja sputatrix

Cited by 3 publications

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Structure and organization of the cardiotoxin genes in Naja naja sputatrix1

Structure and organization of the cardiotoxin genes in Naja naja sputatrix1

Molecular cloning, characterization and evolution of the gene encoding a new group of short‐chain α‐neurotoxins in an Australian elapid, Pseudonaja textilis

Structurally conserved α‐neurotoxin genes encode functionally diverse proteins in the venom of Naja sputatrix1

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Structure and organization of the cardiotoxin genes in Naja naja sputatrix¹

Structure and organization of the cardiotoxin genes in Naja naja sputatrix¹

Structurally conserved α‐neurotoxin genes encode functionally diverse proteins in the venom of Naja sputatrix¹