Montali Aurora, Romanelli Davide, Cappellozza Silvia, Grimaldi Annalisa, de Eguileor Magda, Tettamanti Gianluca
Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy.
CREA - Honey Bee and Silkworm Research Unit, Padua Seat, 35143 Padova, Italy.
Arthropod Struct Dev. 2017 Jul;46(4):518-528. doi: 10.1016/j.asd.2017.05.003. Epub 2017 Jun 16.
Over the years, the silkworm, Bombyx mori, has been manipulated by means of chemical and genetic approaches to improve silk production both quantitatively and qualitatively. The silk is produced by the silk gland, which degenerates quickly once the larva has finished spinning the cocoon. Thus, interfering with this degeneration process could help develop new technologies aimed at ameliorating silk yield. To this end, in this work we studied the cell death processes that lead to the demise of the posterior silk gland of B. mori, directing in particular our attention to autophagy and apoptosis. We focused on this portion of the gland because it produces fibroin, the main component of the silk thread. By using multiple markers, we provide a morphological, biochemical and molecular characterization of the apoptotic and autophagic processes and define their timing in this biological setting. Our data demonstrate that the activation of both autophagy and apoptosis is preceded by a transcriptional rise in key regulatory genes. Moreover, while autophagy is maintained active for several days and progressively digests silk gland cells, apoptosis is only switched on at a very late stage of silk gland demise.
多年来，家蚕一直通过化学和基因方法进行调控，以在数量和质量上提高蚕丝产量。蚕丝由丝腺产生，一旦幼虫完成结茧，丝腺就会迅速退化。因此，干扰这一退化过程有助于开发旨在提高蚕丝产量的新技术。为此，在这项工作中，我们研究了导致家蚕后部丝腺死亡的细胞死亡过程，尤其关注自噬和凋亡。我们将重点放在丝腺的这一部分，因为它产生丝素，即丝线的主要成分。通过使用多种标记物，我们对凋亡和自噬过程进行了形态学、生物化学和分子特征描述，并确定了它们在这种生物学环境中的发生时间。我们的数据表明，自噬和凋亡的激活之前关键调控基因的转录会增加。此外，虽然自噬持续活跃数天并逐渐消化丝腺细胞，但凋亡只在丝腺死亡的非常晚期才开启。
