Mutants of Bacteriophage T4 Defective in the Induction of T4 Endonuclease II

Point mutants in the D2a region of bacteriophage T4 fail to induce T4 endonuclease IV.

We have studied the properties of presumptive point mutants in the D2a region of bacteriophage T4. Dominance tests showed that the D2a mutation was recessive to the wild-type allele. The mutations were shown to map in the D2a region by complementation against rII deletions. The D2a mutations were also located between gene 52 and rIIB by two- and three-factor crosses. The mutants are located at ...

Ligase-defective bacteriophage T4. II. Physiological studies.

The timing of the suppression of gene 30 (deoxyribonucleic acid ligase) mutations by rII mutations was studied by temperature shift-down experiments with a temperature-sensitive rII mutation. The rII function must remain inactivated for about 5 to 8 min at 37 C for suppression to occur, thus making suppression an early function. This result is in agreement with the timing of expression of other...

Properties of bacteriophage T4 mutants defective in DNA polymerase.

G E N E 43 of bacteriophage T4 resides at approximately 320" on the standard map ( STAHL, EDGAR and STEINBERG 1964). Studies of temperatwe-sensitive ( t s ) and amber (am) mutants reveal that gene 43 is the structural gene for the viral DNA polymerase (DE WAARD, PAUL and LEHMAN 1965; WARNER and BARNES 1966; NOSSAL 1969). The T4 DNA polymerase resembles the Escherichia coli DNA polymerase in its...

Cryptic mutants of bacteriophage T4.

HE apparent mutation rate depends upon a number of contingencies: the Tprimary error rate, the probability o€ repair, error avoidance by the apparatus of DNA replication, and the probability of detection. The probability of detection of those base pair substitutions which produce an amino acid substitution appears to be highly variable, and presumably reflects the sensitivity of polypeptide fun...

Endonuclease II - a GIY-YIG enzyme of bacteriophage T4