Cloning and Sequence Analysis of JAK/STAT Pathway Related Major Genes of Silkworm (Bombyx mori)

【Objective】The objective of this study is to identify the elements of JAK/STAT pathway of silkworm,Bombyx mori and determine the function of JAK/STAT pathway related major genes in silkworm.【Method】JAK/STAT pathway related major genes in silkworm were obtained through electronic cloning and conventional RT-PCR.Domain analysis on the related protein were conducted by using bio-softwares online,and the expression profile of these genes in diverse tissues were analysed through microarray database or qPCR.【Result】The silkworm JAK/STAT pathway related major genes including BmSTAT,BmHOP,BmSOCS2,BmSOCS5A,BmSOCS5B,BmSOCS6,BmDRK,Bmken,BmPIAS1,BmPIAS2 and BmPI3K were cloned,respectively,but the homologues of Drosophila Upd1,Upd2 and Upd3 were not cloned.Sequence analysis showed that BmHOP contained CRD_FZ,Kringle domains,transmembrane region and Pkc superfamily protein kinase catalysis domain TyrKc.BmSTAT had two isoforms,which were consisted of SH2,STAT_bind,STAT_int and STAT_alpha domains.Both BmSOCS2A and BmSOCS6A had a conserved SH2 domain and a SOCS box in cloned three genes of BmSOCS family.BmDRK was consisted of SH3 and SH2 domains that connected in series to form SH3-SH2-SH3.BmKen contained BTB and zinc finger domains.BmPIAS1 and BmPIAS2 contained LCR domains.BmPI3K had two conserved SH2 domains.【Conclusion】The JAK/STAT pathway related major genes were cloned successfully in silkworm.The analysis of conserved structural domains suggests that BmHOP is one of the JAK kinases,which phosphorylates the BmSTAT transcription factor and leads to activation of target genes.BmSOCS members,Bmken,BmPIAS1 and BmPIAS2 are negative feedback regulators in the JAK/STAT pathway.