A trypanosomal CCHC-type zinc finger protein which binds the conserved universal sequence of kinetoplast DNA minicircles: isolation and analysis of the complete cDNA from Crithidia fasciculata.
Replication of the kinetoplast DNA minicircle light strand initiates at a highly conserved 12-nucleotide sequence, termed the universal minicircle sequence. A Crithidia fasciculata single-stranded DNA-binding protein interacts specifically with the guanine-rich heavy strand of this origin-associated sequence (Y. Tzfati, H. Abeliovich, I. Kapeller, and J. Shlomai, Proc. Natl. Acad. Sci. USA 89:6891-6895, 1992). Using the universal minicircle sequence heavy-strand probe to screen a C. fasciculata cDNA expression library, we have isolated two overlapping cDNA clones encoding the trypanosomatid universal minicircle sequence-binding protein. The complete cDNA sequence defines an open reading frame encoding a 116-amino-acid polypeptide chain consisting of five repetitions of a CCHC zinc finger motif. A significant similarity is found between this universal minicircle sequence-binding protein and two other single-stranded DNA-binding proteins identified in humans and in Leishmania major. All three proteins bind specifically to single-stranded guanine-rich DNA ligands. Partial amino acid sequence of the endogenous protein, purified to homogeneity from C. fasciculata, was identical to that deduced from the cDNA nucleotide sequence. DNA-binding characteristics of the cDNA-encoded fusion protein expressed in bacteria were identical to those of the endogenous C. fasciculata protein. Hybridization analyses reveal that the gene encoding the minicircle origin-binding protein is nuclear and may occur in the C. fasciculata chromosome as a cluster of several structural genes.
Abeliovich
H
H
Department of Parasitology, Hadassah Medical School, Hebrew University, Jerusalem, Israel.
Tzfati
Y
Y
Shlomai
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D017124:Conserved Sequence; D016831:Crithidia fasciculata / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D018105:DNA, Kinetoplast / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D017125:Genes, Protozoan; D008969:Molecular Sequence Data; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016335:Zinc Fingers / Q000235:genetics* / Q000502:physiology
D018076:DNA, Complementary; D018105:DNA, Kinetoplast; D011993:Recombinant Fusion Proteins