TY - JOUR
T1 - Heterogeneity of minicircles in kinetoplast DNA of Leishmania tarentolae
AU - Challberg, Sharon S.
AU - Englund, Paul T.
N1 - Funding Information:
We thank Drs Mark D. Challberg and Thomas J. Kelly Jr for many helpful discussions, I)rs Joan Marini, Dennis Powers and Nina Federoff for comments on the manuscript, Amy T'so for performing some of the renaturation experiments, and Shirley Metzger for typing this manuscript. We thank Drs P. Borst, J. Donelson, G. Riou, L. Simpson, M. Steinert, K. Stuart and R. Williams for providing us with unpublished manuscripts. This work was supported by National Institutes of Health grant CA13602. One author (S.S.C.) was supported by Public Health Fredoetoral Fellowship Training grant GM00184.
PY - 1980/4/15
Y1 - 1980/4/15
N2 - Kinetoplast DNA, the mitochondrial DNA in trypanosomatids, consists of thousands of DNA circles which are joined in a network. Leishmania tarentolae networks contain 10,000 covalently-closed minicircles, each about 840 base-pairs in length, and less than 50 maxicircles, each about 30,000 base-pairs in length. Minicircles in kinetoplast DNA networks from many species are heterogeneous in nucleotide sequence, and in this paper we describe our studies on L. tarentolae minicircle heterogeneity. Using restriction enzyme analyses we have found that there are three major minicircle sequence classes in this species. Class I minicircles comprise 70% of the total, class II comprise 15%, and class III comprise 7%. The remainder of the minicircles are in minor sequence classes. We have isolated full-length linear restriction fragments from the three major classes and have analyzed the relationship of class I and class II sequences. Each of these two classes contains a population of molecules which appears to be homogeneous based on restriction enzyme mapping, kinetics of reassociation, and thermal chromatography of the reannealed molecules. Similarities in the restriction maps of class I and class II minicircles suggested that they may have related sequences, and we have confirmed this homology by hybridization studies. Thermal chromatography of the heteroduplexes formed between class I and class II minicircles indicates that they differ in about 10 to 15% of their sequences.
AB - Kinetoplast DNA, the mitochondrial DNA in trypanosomatids, consists of thousands of DNA circles which are joined in a network. Leishmania tarentolae networks contain 10,000 covalently-closed minicircles, each about 840 base-pairs in length, and less than 50 maxicircles, each about 30,000 base-pairs in length. Minicircles in kinetoplast DNA networks from many species are heterogeneous in nucleotide sequence, and in this paper we describe our studies on L. tarentolae minicircle heterogeneity. Using restriction enzyme analyses we have found that there are three major minicircle sequence classes in this species. Class I minicircles comprise 70% of the total, class II comprise 15%, and class III comprise 7%. The remainder of the minicircles are in minor sequence classes. We have isolated full-length linear restriction fragments from the three major classes and have analyzed the relationship of class I and class II sequences. Each of these two classes contains a population of molecules which appears to be homogeneous based on restriction enzyme mapping, kinetics of reassociation, and thermal chromatography of the reannealed molecules. Similarities in the restriction maps of class I and class II minicircles suggested that they may have related sequences, and we have confirmed this homology by hybridization studies. Thermal chromatography of the heteroduplexes formed between class I and class II minicircles indicates that they differ in about 10 to 15% of their sequences.
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U2 - 10.1016/S0022-2836(80)80012-X
DO - 10.1016/S0022-2836(80)80012-X
M3 - Article
C2 - 6251227
AN - SCOPUS:0018931745
SN - 0022-2836
VL - 138
SP - 447
EP - 472
JO - Journal of molecular biology
JF - Journal of molecular biology
IS - 3
ER -