A cDNA clone for cyclophilin from Griffithsia japonica and phylogenetic analysis of cyclophilins.

A cDNA clone, designated as Griffithsia japonica cyclophilin-1 (GjCyp-1), was isolated by differential screening of a cDNA library for a red alga, G. japonica. The transcript that corresponded to GjCyp-1 was abundant in vegetative, male, and tetrasporangial thalli, but only the basal level of the transcript was detected in female gametophytes. Determination of the nucleotide sequence of GjCyp-1 identified an open reading frame (ORF), which shared high homologies with cyclophilins that were previously reported in other organisms. Currently available amino acid sequences of eukaryotic cyclophilins were compared in order to examine their phylogenetic relationship to GjCyp-1. A phylogenetic analysis, based on the aligned sequences, showed two major clades - cytosolic cyclophilins (CypA) and ER cyclophilins (CypB). The clade of CypA was divided into six groups - plant, nematode, mammal, euglenozoa, fungi, and platyhelminthes CypA. GjCyp-1 appeared to be closely allied with the euglenozoan CypAs, but constituted an independent lineage. GjCyp-1 showed little relationship with other algal Cyps. A green alga, Chlamydomonas (Chl a + b group), was located in a green plant clade, but a brown alga, Fucus (Chl a + c group), formed an independent clade with a fungus Uromyces (Basidiomycota).