Cyclophilin isoforms from Digitalis lanata. Sequences and Expression during embryogenesis and stress

Two cyolophilin (CyP) nucleotide sequences (DLCYCLO cDNA and DLCYP18 genomi c DNA) from Digitalis lanata are reported. The 765 bp DLCYCLO cDNA contains an open reading frame of 516 nucleotides encoding a protein of 172 amino a cids with a molecular mass of 18,128 Da. The predicted amino acid sequence is highly homologous to those of the A-family of peptidylprolyl cis-trans-i somerases. Southern blot analysis of genomic DNA indicates the existence of a small family of at least three members of related CyP genes in D. lanata . The isolated genomic clone (DLCYP 18) with a high content of A/T in the 5 ' untranslated region lacks introns, but has a putative TATA box and a puta tive polyadenylation site. The nucleotide sequence contains an open reading frame of 516 nucleotides encoding 172 amino acids with a calculated molecu lar mass of 18,055 kDa. DLCYCLO and DLCYP 18 encode two related, but distin ct D. lanata CyPs. CyP mRNA was found in all plant organs tested, in embryo genic cells and in developing somatic embryos of D. lanata. In the course o f embryogenesis CyP transcripts were found at highest levels during early e mbryo development. The level of CyP mRNA increased in response to salt stre ss or treatment with PbNO3. Heat shock treatment decreased the amount of Cy P mRNA. These findings suggest that CyPs are involved in essential biologic al processes during stress and development in D. lanata.