This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sheline, C Articles by Ray, D S Search for Related Content PubMed PubMed Citation Articles by Sheline, C Articles by Ray, D S

 Previous Article  |  Next Article 

Mol Cell Biol. 1989 January; 9(1): 169-176

Replication of DNA minicircles in kinetoplasts isolated from Crithidia fasciculata: structure of nascent minicircles.

Molecular Biology Institute, University of California, Los Angeles 90024.

ABSTRACT

We have previously described an isolated kinetoplast system from Crithidia fasciculata capable of ATP-dependent replication of kinetoplast DNA minicircles (L. Birkenmeyer and D.S. Ray, J. Biol. Chem. 261: 2362-2368, 1986). We present here the identification of two new minicircle species observed in short pulse-labeling experiments in this system. The earliest labeled minicircle species (component A) contains both nascent H and L strands and is heterogeneous in sedimentation and electrophoretic migration. Component A has characteristics consistent with a Cairns-type structure in which the L strand is the leading strand and the H strand is the lagging strand. The other new species (component B) has a nascent 2.5-kilobase linear L strand with a single discontinuity that mapped to either of two alternative origins located 180 degrees apart on the minicircle map. Component B could be repaired to a covalently closed form by Escherichia coli polymerase I and T4 ligase but not by T4 polymerase and T4 ligase. Even though component B has a single gap in one strand, it had an electrophoretic mobility on an agarose gel (minus ethidium bromide) similar to that of a supercoiled circle with three supertwists. Treatment of component B with topoisomerase II converted it to a form that comigrated with a nicked open circular form (replicative form II). These results indicate that component B is a knotted topoisomer of a kinetoplast DNA minicircle with a single gap in the L strand.

This article has been cited by other articles:

• Liu, B., Molina, H., Kalume, D., Pandey, A., Griffith, J. D., Englund, P. T. (2006). Role of p38 in Replication of Trypanosoma brucei Kinetoplast DNA.. Mol. Cell. Biol. 26: 5382-5393 [Abstract] [Full Text]  
• Engel, M. L., Hines, J. C., Ray, D. S. (2001). The Crithidia fasciculata RNH1 gene encodes both nuclear and mitochondrial isoforms of RNase H. Nucleic Acids Res 29: 725-731 [Abstract] [Full Text]  
• Abu-Elneel, K., Kapeller, I., Shlomai, J. (1999). Universal Minicircle Sequence-binding Protein, a Sequence-specific DNA-binding Protein That Recognizes the Two Replication Origins of the Kinetoplast DNA Minicircle. J. Biol. Chem. 274: 13419-13426 [Abstract] [Full Text]  
• Tzfati, Y., Abeliovich, H., Avrahami, D., Shlomai, J. (1995). Universal Minicircle Sequence Binding Protein, a CCHC-type Zinc Finger Protein That Binds the Universal Minicircle Sequence of Trypanosomatids. J. Biol. Chem. 270: 21339-21345 [Abstract] [Full Text]