α-conopeptides specifically expressed in the salivary gland of Conus pulicarius
α-conopeptides specifically expressed in the salivary gland of Conus pulicarius
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DOI：
10.1016/j.toxicon.2008.05.004
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发表时间：
2008-07-01
期刊：
影响因子：
2.8
通讯作者：
Kantor, Yuri I.
中科院分区：
文献类型：
--
作者：
Biggs, Jason S.;Olivera, Baldomero M.;Kantor, Yuri I.
迄今为止，对锥螺毒液进行的研究已将这种复杂的神经活性肽混合物的起源完全归因于毒液管腔内衬的分泌细胞的基因表达。然而，唾液腺等特殊组织也会将其内容物分泌到前肠中，并可能将一些毒液成分注射到目标动物体内；这里报告了支持这种可能性的证据。对从圆锥芋唾液腺创建的 cDNA 文库进行序列分析，揭示了两个转录本的表达，这两个转录本的预测基因产物在翻译后处理后，与属于 α-芋螺毒素家族的成熟芋螺肽惊人地相似。这两个转录物，如α-芋螺毒素转录物，推测编码含有保守的A-超家族半胱氨酸模式(CC-C-C)的成熟肽，但不存在高度保守的A-超家族信号序列。对在同一 C. pulicarius 标本的毒液管中表达的 A 超家族成员的分析揭示了三个假定的 a-芋螺毒素序列；在毒液管 cDNA 文库中未发现唾液腺转录本，表明这些 α-芋螺毒素是唾液腺特异性的。因此，唾液腺表达芋螺毒素样基因产物可能会增加芋螺毒液的复杂性。 (C) 2008 Elsevier Ltd. 保留所有权利。
To date, studies conducted on cone snail venoms have attributed the origins of this complex mixture of neuroactive peptides entirely to gene expression by the secretory cells lining the lumen of the venom duct. However, specialized tissues such as the salivary glands also secrete their contents into the anterior gut and could potentially contribute some venom components injected into target animals; evidence supporting this possibility is reported here. Sequence analysis of a cDNA library created from a salivary gland of Conus pulicarius revealed the expression of two transcripts whose predicted gene products, after post-translational processing, strikingly resemble mature conopeptides belonging to the alpha-conotoxin family. These two transcripts, like a-conotoxin transcripts, putatively encode mature peptides containing the conserved A-superfamily cysteine pattern (CC-C-C) but the highly conserved A-superfamily signal sequences were not present. Analysis of A-superfamily members expressed in the venom duct of the same C. pulicarius specimens revealed three putative a-conotoxin sequences; the salivary gland transcripts were not found in the venom duct cDNA library, suggesting that these alpha-conotoxins are salivary gland specific. Therefore, expression of conotoxin-like gene products by the salivary gland could potentially add to the complexity of Conus venoms. (C) 2008 Elsevier Ltd. All rights reserved.