title: Identification of a putative invertebrate helical cytokine similar to the ciliary neurotrophic factor/leukemia inhibitory factor family by PSI-BLAST-based approach.
abstract: Most of our knowledge of helical cytokine-like molecules in invertebrates relies on functional assays and similarities at the physicochemical level. It is hard to predict helical cytokines in invertebrates based on sequences from mammals and vertebrates, because of their long evolutionary divergence. In this article, we collected 12 kinds of fish cytokines and constructed their respective consensus sequences using hidden Markov models; then, the conserved domains region of each consensus sequence were further extracted by the SMART tool, and used as the query sequence for PSI-BLAST analysis in Drosophila melanogaster. After two filtering processes based on the properties of helical cytokines, we obtained one protein named CG14629, which shares 25% identities/46% positives to fish M17 cytokine in the half length of the N-terminus. Considering the homology between M17 and LIF/CNTF (leukemia inhibitory factor/ciliary neurotrophic factor), and the close relationship between Dome, the putative cytokine receptor in Drosophila cells, and LIFR/CNTFR (LIF receptor/CNTF receptor), the results suggest that CG14629 is a good candidate for the helical cytokine ortholog in D. melanogaster.
authors.affiliation: School of Life Science, Fudan University, Shanghai, People's Republic of China.
authors.forename: Gong
authors.initials: G
authors.lastname: Cheng
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Zuofeng
authors.initials: Z
authors.lastname: Li
authors.forename: Xinyi
authors.initials: X
authors.lastname: Liu
authors.forename: Weiyao
authors.initials: W
authors.lastname: Yan
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhong
authors.forename: Zhaoxin
authors.initials: Z
authors.lastname: Zheng
mesh_terms: D000818:Animals; D020934:Ciliary Neurotrophic Factor / Q000737:chemistry / Q000235:genetics*; D019295:Computational Biology; D003198:Computer Simulation; D016384:Consensus Sequence / Q000235:genetics / Q000276:immunology; D016207:Cytokines / Q000737:chemistry / Q000235:genetics*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics*; D004331:Drosophila melanogaster; D019143:Evolution, Molecular; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics*; D005399:Fishes; D017433:Protein Structure, Secondary; D020801:Receptor, Ciliary Neurotrophic Factor / Q000737:chemistry / Q000235:genetics; D018123:Receptors, Interleukin / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D040681:Structural Homology, Protein; D013329:Structure-Activity Relationship
chemical_list: D020934:Ciliary Neurotrophic Factor; D016207:Cytokines; D029721:Drosophila Proteins; D029941:Fish Proteins; D020801:Receptor, Ciliary Neurotrophic Factor; D018123:Receptors, Interleukin; C444499:dome protein, Drosophila