The mRNA of DEAD box protein p72 is alternatively translated into an 82-kDa RNA helicase.
p68 and p72 are two highly related DEAD box proteins with similar biochemical activities in the nucleus of vertebrate cells; it is unknown whether they have redundant or differential in vivo functions. We report on a third member of this subfamily that is alternatively expressed from p72 mRNA. A detailed analysis of HeLa p72 mRNA was performed. It has an overall length of more than 5 kb and contains a 0.75-kb 5'-untranslated region and a 3'-untranslated region of 2.5 kb. Its open reading frame extends to nucleotide -243 upstream of the first in-frame AUG (A in the AUG triplet is +1) which serves as the p72 translation initiator codon. We provide evidence that alternative translation at a non-AUG within the extra coding region of this mRNA yields an 82-kDa protein (p82). Immunological studies substantiate that p82 is a naturally existing p72 variant and that both proteins are expressed at similar concentrations. p82 purified from HeLa cells is an ATP-dependent RNA helicase with biochemical properties almost identical to those of p72.
Uhlmann-Schiffler
Heike
H
Fachbereich Medizinische Biochemie und Molekularbiologie, Fachrichtung Theoretische Medizin, Universität des Saarlandes, D-66421 Homburg, Germany.
Rössler
Oliver G
OG
Stahl
Hans
H
D020121:5' Untranslated Regions; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D017398:Alternative Splicing / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002467:Cell Nucleus / Q000378:metabolism; D053487:DEAD-box RNA Helicases; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012045:Regulatory Sequences, Nucleic Acid
D020121:5' Untranslated Regions; D009687:Nuclear Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D000251:Adenosine Triphosphatases; C102004:DDX17 protein, human; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases