The DNA content in the silk glands of the non-mulberry silkworm Philosamia ricini increases continuously during the fourth and fifth instars of larval development indicating high levels of DNA replication in this terminally differentiated tissue. Concomitantly, the DNA polymerase alpha activity also increases in the middle and the posterior silk glands during development, reaching maximal levels in the middle of the fifth larval instar. A comparable level of DNA polymerase delta/epsilon was also observed in this highly replicative tissue. The DNA polymerase alpha-primase complex from the silk glands of P. ricini has been purified to homogeneity by conventional column chromatography as well as by immunoaffinity techniques. The molecular mass of the native enzyme is 560 kDa and the enzyme comprises six non-identical subunits. The identity of the enzyme as DNA polymerase alpha has been established by its sensitivity to inhibitors such as aphidicolin, N-ethylmaleimide, butylphenyl-dGTP, butylanilino-dATP and antibodies to polymerase alpha. The enzyme possesses primase activity capable of initiating DNA synthesis on single-stranded DNA templates. The tight association of polymerase and primase activities at a constant ratio of 6:1 is observed through all the purification steps. The 180 kDa subunit harbours the polymerase activity, while the primase activity is associated with the 45 kDa subunit.
Skip Nav Destination
Follow us on Twitter @Biochem_Journal
Article navigation
March 1994
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkAdvertising
Research Article|
March 15 1994
DNA polymerase α-primase complex from the silk glands of the non-mulberry silkworm Philosamia ricini Available to Purchase
S Niranjanakumari;
S Niranjanakumari
1Microbiology and Cell Biology Department and Centre for Genetic Engineering, Indian Institute of Science, Bangalore 560 012, India
Search for other works by this author on:
K P Gopinathan
K P Gopinathan
1Microbiology and Cell Biology Department and Centre for Genetic Engineering, Indian Institute of Science, Bangalore 560 012, India
Search for other works by this author on:
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1994 The Biochemical Society, London
1994
Biochem J (1994) 298 (3): 529–535.
Citation
S Niranjanakumari, K P Gopinathan; DNA polymerase α-primase complex from the silk glands of the non-mulberry silkworm Philosamia ricini. Biochem J 15 March 1994; 298 (3): 529–535. doi: https://doi.org/10.1042/bj2980529
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Biochemical Society Member Sign in
Sign InSign in via your Institution
Sign in via your InstitutionGet Access To This Article
Cited By
Follow us on Twitter @Biochem_Journal
Open Access for all
We offer compliant routes for all authors from 2025. With library support, there will be no author nor reader charges in 5 journals. Check here |
![]() View past webinars > |