Immunocytochemical localization of chick DNA polymerases α and β⁺

Abstract

An immunofluorescent method using specific antibodies was employed to detect DNA polymerases alpha and beta in chick cells. With monoclonal antibodies produced by four independent hybridoma clones, most of the DNA polymerase alpha was shown to be present in nuclei of cultured chick embryonic cells. With a polyclonal, but highly specific, antibody against DNA polymerase beta, this enzyme was also shown to be present in nuclei. DNA polymerase alpha was detected in proliferating cells before cell contact and in lesser amount in resting cells after cell contact, indicating that its content is closely correlated with cell proliferation. On the other hand, similar amounts of DNA polymerase beta were detected in proliferating and resting cells. Furthermore, DNA polymerase beta was detected in nuclei of most cells, while DNA polymerase alpha was detected only in large round nuclei in seminiferous tubules of chick testis. DNA polymerase alpha is presumably present in cells that are capable of DNA replication, and during the cell cycle it seems to remain in the nuclei during the G1, S, and G2 phases, but to leave from condensed chromatin for the cytoplasm during the mitotic phase.

Differential inhibition of human placental DNA polymerases δ and α by BuPdGTP and BuAdATP

“…DNA polymerase a Is generally regarded as the enyzme involved in replication, In contrast to polymerase B and y. Evidence for the Involvement of polymerase a in DNA replication has come from extensive studies of inhibitors of DNA synthesis, particularly by aphidicolin, which Inhibits DNA synthesis jl v and also selectivelyinhibits polymerase e activity (but not B and y) in vitro (1-3), as well as demonstrations of the nuclear localization of the enzyme (4)(5)(6) and the inhibition of DNA synthesis in permeabilized cells by anti-alpha antibodies (7). More recently, a novel mammalian DNA polymerase, polymerase 8, has been described (8-13).…”

Detection of the growth fraction in colorectal tumours by a monoclonal antibody against DNA polymerase α

“…DNA polymerase a, the major DNA polymerase in growing mammalian cells, is the most important enzyme in DNA replication (Weissbach, 1979;Sarngadharan et al, 1978). It is believe that DNA polymerase a localises in the nucleus of proliferative cells in the G1, S and G2 phases of transformed human cells, and shows a scattered cytoplasmic distribution in M phase of the cell cycle, but that it is not found in resting cells (Bensch et al, 1982;Matsukage et al, 1983;Nakamura et al, 1984). The monoclonal antibody against DNA polymerase a which we have used was reported by Masaki et al in 1982. This antibody recognises a nuclear antigen which is expressed in cycling cells.…”

On the presence of DNA polymerase α in human lymphocyte nuclei and chromosomes

“…The intracellular localization of this enzyme is still controversial. In fact, although some reports suggest its presence in the cytoplasm (Bollum, 1975;Brown et aL, 1981), other data indicate the nuclear localization of DNA polymerase (Masaki et al, 1982;Matsukage et a!., 1983). In particular, it has been found in association with the nuclear matrix which, as a consequence, is believed to play some fundamental role in DNA synthesis (Foster & Collins, 1985;Smith & Berezney, 1983;Collins & Chu, 1987).…”