Insects produce silk to form cocoons,nests,and webs,which are important for their survival and reproduction.However,little is known about the molecular mecha-nism of silk protein synthesis at the translation level.The...Insects produce silk to form cocoons,nests,and webs,which are important for their survival and reproduction.However,little is known about the molecular mecha-nism of silk protein synthesis at the translation level.The solute carrier family 7(SLC7)genes are involved in activating the target of rapamycin complex 1(TORC1)signaling pathway and protein translation process,but the physiological roles of SLC7 genes in silk-producing insects have not been reported.Here,we found that amino acid signaling regulates silk protein synthesis and larval development via the L-type amino acid trans-porter 1(LAT1;also known as SLC7A5)in Bombyx mori.A total of 12 SLC7 homologs were identified in the silkworm genome,among which BmSLC7A5 was found to be a silk gland-enriched gene and may be involved in leucine transport.Bioinformatics analy-sis indicated that SLC7A5 displays high homology and a close phylogenetic relationship in silk-producing insects.Subsequently,we found that leucine treatment significantly in-creased silk protein synthesis by improving the transcription and protein levels of silk genes.Furthermore,systemic and silk gland-specific knockout of BmSLC7A5 led to de-creased silk protein synthesis by inhibiting TORC1 signaling,and somatic mutation also resulted in arrested development from the 5th instar to the early pupal stage.Altogether,our study reveals that BmSLC7A5 is involved in regulating silk protein synthesis and larval development by affecting the TORC1 signaling pathway,which provides a new strategy and target for improving silk yield.展开更多
基金Thiswork was supported bygrants fromthe NationalNaturalScience FoundationofChina(31772532)the China Postdoctoral Science Foundation(2022MD713704)the Chongqing Science and Technology Bureau(cstc2021ljcyj-bshX0222 and jbky20210004).
文摘Insects produce silk to form cocoons,nests,and webs,which are important for their survival and reproduction.However,little is known about the molecular mecha-nism of silk protein synthesis at the translation level.The solute carrier family 7(SLC7)genes are involved in activating the target of rapamycin complex 1(TORC1)signaling pathway and protein translation process,but the physiological roles of SLC7 genes in silk-producing insects have not been reported.Here,we found that amino acid signaling regulates silk protein synthesis and larval development via the L-type amino acid trans-porter 1(LAT1;also known as SLC7A5)in Bombyx mori.A total of 12 SLC7 homologs were identified in the silkworm genome,among which BmSLC7A5 was found to be a silk gland-enriched gene and may be involved in leucine transport.Bioinformatics analy-sis indicated that SLC7A5 displays high homology and a close phylogenetic relationship in silk-producing insects.Subsequently,we found that leucine treatment significantly in-creased silk protein synthesis by improving the transcription and protein levels of silk genes.Furthermore,systemic and silk gland-specific knockout of BmSLC7A5 led to de-creased silk protein synthesis by inhibiting TORC1 signaling,and somatic mutation also resulted in arrested development from the 5th instar to the early pupal stage.Altogether,our study reveals that BmSLC7A5 is involved in regulating silk protein synthesis and larval development by affecting the TORC1 signaling pathway,which provides a new strategy and target for improving silk yield.
