Identification of a human ABCC10 orthologue in Catharanthus roseus reveals a U12-type intron determinant for the N-terminal domain feature

Abstract

ABC (ATP-binding cassette) transporters are members of a large superfamily of proteins that utilize ATP hydrolysis to translocate a wide range of substrates across biological membranes. In general, members of C subfamily (ABCC) are structurally characterized by an additional (N-terminal) transmembrane domain (TMD0). Phylogenetic analysis of plant ABCCs separates their protein sequences into three distinct clusters: I and II are plant specific whereas cluster III contains both human and plant ABCCs. Screening of the Plant Medicinal Genomics Resource database allowed us to identify 16 ABCCs partial sequences in Catharanthus roseus; two of which belong to the unique CrABCC1 transcript that we identified in cluster III. Genomic organization of CrABCC1 TMD0 coding sequence displays an AT-AC U12-type intron that is conserved in higher plant orthologues. We showed that CrABCC1, like its human orthologue ABCC10, produces alternative transcripts that encode protein sequences with a truncated form of TMD0 without the first transmembrane span (TM1). Subcellular localization of CrABCC1 TMD0 variants using yellow fluorescent protein fusions reveals that the TM1 is required for a correct routing of the TMD0 to the tonoplast. Finally, the specific repartition of CrABCC1 orthologues in some species suggests that this gene was lost several times during evolution and that its physiological function may, rely on a common feature of multicellular eukaryotes.

ASG2 is a farnesylated DWD protein that acts as ABA negative regulator in Arabidopsis

“…After sequencing, the constructs were used for Arabidopsis protoplasts transfection as described in El Guizani et al . (). Nucleus was stained with 50 µg mL −1 4′,6‐diamidino‐2‐phenylindole (DAPI).…”

Role of Different Transporting Systems in the Secretion of Alkaloids by Hairy Roots of Catharanthus roseus (L) G. Don

“…However, the expression of the CjMDR1 gene, a transmembrane ABC transporter from Coptis japonica, in C. roseus cells, produced an increase in the accumulation of ajmalicine and tetrahydroalstonine, alkaloids from C. roseus but not of berberine, the main substrate of the CjMDR1 transporter [9]. Recently, the screening of the Plant Medicinal Genomics Resource database allowed to El-Guizani et al [10] to identify 16 ABC transporters partial sequences in C. roseus.…”