De Novo Biosynthesis of Deoxyribonucleic Acid Polymerase during Wheat Embryo Germination

Abstract

An 8-fold enhancement in the activity of a DNA-dependent DNA polymerase was found in extracts from germinating wheat (Triticum vulgare var. Florence) embryos, as compared to the activity found in extracts from ungerminated embryos. The enhancement of this activity during the first hours of germination is concomitant to the increase of a DNase activity. The two activities could be separated and the increased level of the DNA polymerase upon germination was observed in an enzymatic fraction which contains very low DNase activity. Addition of the protein synthesis inhibitor, blasticidin S, to germinating wheat embryos, reduced the increase in DNA polymerase. Incorporation of radioactive amino acids into a phosphocellulose preparation, which contains the DNA polymerase starts during the first 6 hours of germination. The amount of radioactivity incorporated is doubled in the next 6 hours, and the incorporation is continued between 12 and 18 hours of germination.

Oxalate, Germins, and Higher‐Plant Pathogens

“…There was very good reason to view germins as being kindred to cyclins. Growth in the wheat-embryo system (7) was, at first, couched in the context of DNA synthesis (61), and was therefore focused on cell-division growth (62), but when postgerminative growth was later recast in the context of water uptake, in the absence of net DNA syn- Figure 3. The cartoon portrays a wheat embryo protected by a coat capable of microcidal activity.…”

Factors affecting the onset of deoxyribonucleic acid synthesis during wheat embryo germination. Study of the changes in DNA polymerases A, B and C and the pool of DNA precursors

“…DNA synthesis seems to be dependent on protein synthesis during the first hours of germination. On the basis of studies with blasticidine S, an inhibitor of eukaryotic protein synthesis, it has been proposed that the limiting factor in the start of DNA synthesis is the biosynthesis of DNA polymerase (Mory et al, 1972(Mory et al, , 1975.…”

Studies on a DNA polymeraseγ‐like enzyme from wheat embryos

“…A cytoplasmic enzyme having a sedimentation coefficient of 7.0 S has been described in tobacco cell cultures [17] as well as a DNA polymerase from germinated wheat embryos having a mol. wt of 230 000 [18]. None of these enzymes is able to recognize poly rA-dT~ 2 as a template.…”