Abstract: 【Aim】 A large number of genomic transcripts in both prokaryotes and eukaryotes are non-protein coding RNAs (ncRNAs). Accumulated evidences show that ncRNAs play important roles during the development of the silkworm, Bombyx mori. This study aims to explore the molecular mechanisms of ncRNAs in the nervous development of the silkworm. 【Methods】 Real-time PCR was used to study the expression of 22 ncRNAs and three neighboring genes of ncRNAs in the nervous system of the silkworm. 【Results】 Eight ncRNAs including a C/D box snoRNA, four H/ACA box snoRNAs and three unclassified ncRNAs were accumulated much more in the ventral thoracic nerves than in the nerves of head in the 5th instar larvae of the silkworm. Especially, the expression levels of snoRNA Bm-51, Bm-18 and Bm-86 in the ventral thoracic nerves were 23, 5 and 4.7 times as high as those in the nerves of head, respectively. Further studies showed that the expression of host genes was consistent with that of the three intron-origin ncRNAs, with more accumulation in the ventral thoracic nerves than in the nerves of head. 【Conclusion】 ncRNAs with higher expression in the ventral thoracic nerves might play roles in the activity of nerves through participating in the regulation of their neighboring genes. The results provide a molecular basis for the functional study of ncRNAs in the silkworm, as well as new clues for the lepidopterous pest control.

Key words: Bombyx mori, nervous system, non-coding RNAs, expression profiles, ventral thoracic nerves