Alternative interpretation of the molecular structure and somatic genetics of acid phosphatase-1 inTetrahymena pyriformis
✍ Scribed by Eduardo Orias
- Publisher
- Springer
- Year
- 1973
- Tongue
- English
- Weight
- 208 KB
- Volume
- 9
- Category
- Article
- ISSN
- 0006-2928
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✦ Synopsis
Acid phosphatase-1 isozymes with different electrophoretic mobilities were discovered in syngen 1 of Tetrahyrnena pyriforrnis (Allen et al., 1963a, b). The careful and intensive studies of Allen and collaborators (Allen, 1967(Allen, , 1971;; Allen et al., 1963a b,) have established the following main picture concerning the isozymes and their genetic determination: (1) The electrophoretic mobility differences are due to the presence of two different alleles of a single gene, assumed to be the structural gene for the acid phosphatase monomer. The homozygote for each allele has a single main molecular species of acid phosphatase-1 (cell types P1 and P5, respectively). (2) A "young" heterozygote (less than 40 binary fissions old) produces three molecular species, called isozymes 1, 3, and 5, respectively (cell type P~,3,5). Isozymes 1 and 5 correspond to the molecular species present in the respective homozygotes. Isozyme 3, which has an intermediate electrophoretic mobility, is characteristic of the heterozygote. (3) Beginning at about 50 fissions after sexual reorganization, stable subclones begin to segregate out from the heterozygotes; these express only isozyme 1 or 5, respectively. (4) If an unsegregated heterozygote is grown for over 100 fissions, new molecular species (isozymes 2 and 4) appear, interspersed in electrophoretic mobility between isozymes 1, 3, and 5. This cell possessing all five isozymes is designated P1,2,3,4,s. (5) From this novel cell type, three stable classes of segregants can be obtained by clonal selection, expressing exclusively either isozyme 1, or isozyme 3, or isozyme 5, respectively.