Arabidopsis expresses two genes that encode polypeptides similar to the yeast RNA polymerase I and III AC40 subunit.
A 40-kDa subunit in eukaryotic RNA polymerases (Pol) I and III (e.g., yeast yAC40) is related in a part of its aa sequence to the alpha subunit of prokaryotic Pol and to a 35-44-kDa subunit in Pol II (e.g., yeast yB44). We have cloned two cDNAs, AtRPAC42 and AtRPAC43, from an Arabidopsis thaliana (At) (ecotype Columbia) lambda Yes expression library that encode Pol I and III subunits related to yAC40. The aa sequences derived from the cDNA clones were found to be 72% identical to each other and 40% identical to yeast Pol I and III subunits yAC40, but only 30% identical to yeast Pol II subunit yB44. While most other nuclear Pol genes identified to date are single-copy genes, two genes encode 42 and 43-kDa subunits of At Pol I and/or III. A 42-kDa subunit with identical mobility in SDS-PAGE to the aAC42 in vitro translated subunit is found in Pol III purified from At suspension culture cells.
Ulmasov
T
T
Department of Biochemistry, University of Missouri, Columbia 65211, USA.
Larkin
R M
RM
Guilfoyle
T J
TJ
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry; D015870:Gene Expression; D017343:Genes, Plant; D008969:Molecular Sequence Data; D012318:RNA Polymerase I / Q000235:genetics*; D012320:RNA Polymerase III / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D012333:RNA, Messenger; D012321:DNA-Directed RNA Polymerases; D012318:RNA Polymerase I; D012320:RNA Polymerase III