THE UTILIZATION OF LEAKY AD-3 MUTANTS OF NEUROSPORA CRASSA IN HETEROKARYON TESTS FOR ALLELIC COMPLEMENTATION
Journal Article
·
· Mutation Research
Heterokaryon tests were made on pairwise combinations of leaky ad-3 mutants of Neurospora crassa to test for allelic complementation at the ad-3A and ad-3B loci. Since leaky mutants produce a protein, such heterokaryon tests should provide a critical test for the occurrence of allelic complementation at these two loci. A comparison was also made with similar tests on nonleaky ad-3A or ad-3B mutants. No evidence for allelic complementation was found in any pairwise combination of 28 leaky and 38 nonleaky ad-3A mutants, providing additional evidence that ad-3A is a one-complon locus. Among the ad-3B mutants the percentage of complementing mutants was 100% (50/50) among leaky mutant combinations and 2.4% (7/290) among nonleaky mutant combinations. At least 71% (25/35) of the leaky mutants had different complementation patterns. The matrix of heterokaryon tests on the leaky mutant combinations specifies a complementation map with 14 complons, whereas the matrix of the heterokaryon tests on the nonleaky mutant combinations specifies a complementation map with only two complons. The interaction matrix of all of the heterokaryon tests on leaky and nonleaky ad-3B mutants specifies a linear complementation map of the ad-3B cistron consisting of 20 complons. The complementation patterns of the nonleaky ad-3B mutants differed from those of the leaky mutants in the average number of complons covered (13.1 versus 2.2). This is believed to reflect a difference in the primary structure of the polypeptides specified by each class of mutant. In the present paper a comparison is made between heterokaryon tests for allelic complementation among the leaky mutants and nonleaky mutants at the ad-3A and ad-3B loci. The results of these tests indicate that allelic complementation does not occur at the ad-3A i,ocus even among leaky mutants. Tests on the ad-3B mutants not only indicate that all of the leaky ad23B mutants show allelic complementation but that it occurs among some of the nonleaky mutants as well. However, comparison of the complementation map of the ad-3B cfstron specified by the leaky mutants with that specified by the nonleaky mutants provides a striking contrast in the results obtained with these two different approaches.
- Research Organization:
- Oak Ridge National Lab., TN
- Sponsoring Organization:
- US Atomic Energy Commission (AEC)
- DOE Contract Number:
- W-7405-ENG-26
- NSA Number:
- NSA-20-018347
- OSTI ID:
- 4567243
- Report Number(s):
- ORNL-P-1160; DOI: 10.1016/0027-5107(66)90003-0
- Journal Information:
- Mutation Research, Journal Name: Mutation Research Journal Issue: 1 Vol. Vol: 3; ISSN 0027-5107
- Publisher:
- Elsevier B.V.
- Country of Publication:
- United States
- Language:
- English
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Thu Feb 28 23:00:00 EST 1963
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Sun May 01 00:00:00 EDT 1960
· Genetics (U.S.)
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OSTI ID:4142064
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Conference
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Sun Dec 31 23:00:00 EST 1972
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OSTI ID:4312433