skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Mammalian. cap alpha. -polymerase: cloning of partial complementary DNA and immunobinding of catalytic subunit in crude homogenate protein blots

Journal Article · · Biochemistry; (United States)
OSTI ID:6524689

A new polyclonal antibody against the ..cap alpha..-polymerase catalytic polypeptide was prepared by using homogeneous HeLa cell..cap alpha..-polymerase. The antibody neutralized ..cap alpha..-polymerase activity and was strong and specific for the ..cap alpha..-polymerase catalytic polypeptide (M/sub r/ 183,000) in Western blot analysis of crude extracts of HeLa cells. The antibody was used to screen a cDNA library of newborn rat brain poly(A+) RNA in lambdagt11. A positive phage was identified and plaque purified. This phage, designated lambdapol..cap alpha..1.2, also was found to be positive with an antibody against Drosophila ..cap alpha..-polymerase. The insert in lambdapol..cap alpha..1.2 (1183 base pairs) contained a poly(A) sequence at the 3' terminus and a short in-phase open reading frame at the 5' terminus. A synthetic oligopeptide (eight amino acids) corresponding to the open reading frame was used to raise antiserum in rabbits. Antibody affinity purified from this serum was found to be immunoreactive against purified ..cap alpha..-polymerase by enzyme-linked immunosorbent assay and was capable of immunoprecipitating ..cap alpha..-polymerase. This indicated the lambdapol..cap alpha..1.2 insert encoded an ..cap alpha..-polymerase epitope and suggested that the cDNA corresponded to an ..cap alpha..-polymerase mRNA. This was confirmed in hybrid selection experiments using pUC9 containing the cDNA insert and poly(A+) RNA from newborn rat brain; the insert hybridized to mRNA capable of encoding ..cap alpha..-polymerase catalytic polypeptides. Northern blot analysis of rat brain poly(A+) RNA revealed that this mRNA is approx.5.4 kilobases.

Research Organization:
National Institutes of Health, Bethesda, MD
OSTI ID:
6524689
Journal Information:
Biochemistry; (United States), Vol. 26:3
Country of Publication:
United States
Language:
English