Mutants lines

Fig. 8. Avoidance behavior towards an unprotected area displayed by the offspring of mice treated with the mutagen ethyl-nitrosourea (ENU). The behavior of the offspring is compared to a mean value calculated from the genetic background strain. Mice differing more than 2.75 SDs from the mean value (indicated by circles) are considered to be potential mutants and, after confirmation of the phenotype, are selected as founders for a ENU-mutant line...

Two mutant lines of yellow mosaic virus resistant barley were found in ca. 50,000 M2 families. The character of the resistance in a field was not changed over three generations [114]. 

Much of the information on ANS has come not from studies on enzyme extracts but from analysis of DNA sequences and recombinant proteins. Sequences for the ANS were first isolated using transposon generated mutant lines of A. majus and Z. mays They encoded proteins of 40 to 41 kDa that were found to have similarity to 20GDs, during a study on a nonflavonoid enzyme. This sequence-based identification was confirmed by the in vitro assay of the recombinant Perilla frutescens protein, and subsequent assays on recombinant ANS from a range of species that confirmed the requirement for Fe, 20G, and ascorbate. Sequence comparisons show that ANS is more closely related to flavonol synthase (FLS), another 20GD, than to F3H. 

Probably nearly 200 rodent mutant lines have now been isolated and tested by genetic complementation for their genetic identity. Complementation at first involved cell-fusion techniques and this finally established the existence of 11 complementation groups, each representing a single gene. 

Takahashi, K., Banba, H., Kikuchi, A., Ito, M., Nakamura, S. 1994. An induced mutant line lacking the a-subunit of P-conglycinin in soybean (Glycine max (L) Merril). Breeding Sci 44 65-66. 

Although neither TK. cells nor HPRT- cells will grow separately in HAT medium it is found that mixed populations of these two mutant lines will grow in HAT medium (see Fig. 13.3). 

This mutant line will be a useful model for testing the effectiveness of pharmacological intervention in preventing cell loss, an important goal of epilepsy treatment in human patients. Since other Na" " channels are also expressed in hippocampal neurons, it seems likely that delayed inactivation of SCN1A, SCN3A or SCN8A could also result in seizures. 

HMG-CoA reductase activity and LDL receptor levels always appear to change in the same direction in cells exposed to different levels of LDL. Similarly, a mutant line of Chinese hamster ovary (CHO) cells exposed to delipidated serum expresses low levels of both HMG-CoA reductase and LDL receptor activities compared to normal cells [88], Taken together, this evidence suggests coordinate expression of these two activities. 

Other large-scale alterations in membrane fatty acid composition and phenotypes have been obtained by creation of multiple-mutant lines. When mutants defective in ER... 

---