Identification and characterization of extrachromosomal circular DNA in the silk gland of Bombyx mori

The silk gland cells of silkworm are special cells in which division occurs only at the embryonic stage. Throughout the larval stage, the silk gland cells only replicate DNA in the nucleus without cell division. The extrachromosomal circular DNAs (eccDNAs) have not yet been reported in the silk gland of silkworms. Herein, Zhuet  al. have explored the characterization of eccDNAs in the posterior silk gland of silkworms. Motif analysis revealed that dual direct repeats flanking the 5 ′ and 3′ breaking points of eccDNA might support possible models for eccDNA generation. Genomic annotation of the eccDNA found that silk protein genesfib-H,fib-L, andP25, as well as the transcription factorsSGF andsage, which play an important regulatory role in silk protein synthesis, could be carried by eccDNAs. EccDNAfib-L could promote the transcription offib-L gene. AbstractThe silk gland cells of silkworm are special cells which only replicate DNA in the nucleus without cell division throughout the larval stage. The extrachromosomal circular DNAs (eccDNAs) have not yet been reported in the silk gland of silkworms. Herein, we have explored the characterization of eccDNAs in the posterior silk gland of silkworms. A total of 35  346 eccDNAs were identified with sizes ranging from 30 to 13 569 549 bp. Motif analysis revealed that dual direct repeats are flanking the 5′ and 3′ breaking points of eccDNA. The sequences exceeding 1 kb length in eccDNAs present palindromic sequence chara...

Source: Insect Science - April 10, 2023 Category: Biology Authors: Min Zhu, Xinyu Tong, Qunnan Qiu, Jun Pan, Shulin Wei, Yuming Ding, Yongjie Feng, Xiaolong Hu, Chengliang Gong Tags: ORIGINAL ARTICLE Source Type: research