A human common nuclear matrix protein homologous to eukaryotic translation initiation factor 4A.
Amino acid sequencing and mass spectrometry revealed identity of a human nuclear matrix protein, termed hNMP 265, with a predicted protein of gene KIAA0111. Two-dimensional electrophoresis and Northern hybridization showed the protein to ubiquitously occur in various human cell types. Exhibiting DEAD-box motifs characteristic for RNA helicases, hNMP 265 is highly similar to the human initiation factors eIF4A-I and -II. On the other hand, hNMP 265 greatly differs from the initiation factors by a N-terminal sequence rich in charged amino acids. Sequence searches and alignments indicate proteins related to hNMP 265 in other eukaryotes. Chimeras between hNMP 265 and green fluorescence protein or hapten appeared as speckles in extranucleolar regions in the nucleus, but not in the cytoplasm. Experiments with tagged deletion mutants indicated that the N-terminal amino acid sequence is necessary for nuclear localization. A putative role of hNMP 265 in pre-mRNA processing is discussed.
Holzmann
K
K
Institute of Tumor Biology-Cancer Research, University of Vienna, Borschkegasse 8a, Vienna, A-1090, Austria.
Gerner
C
C
Pöltl
A
A
Schäfer
R
R
Obrist
P
P
Ensinger
C
C
Grimm
R
R
Sauermann
G
G
D000595:Amino Acid Sequence; D000818:Animals; D053487:DEAD-box RNA Helicases; D039601:Eukaryotic Initiation Factor-4A; D006367:HeLa Cells; D006801:Humans; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D015530:Nuclear Matrix / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification; D010448:Peptide Initiation Factors / Q000737:chemistry*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D009687:Nuclear Proteins; D010448:Peptide Initiation Factors; D011993:Recombinant Fusion Proteins; D039601:Eukaryotic Initiation Factor-4A; C403493:EIF4A3 protein, human; D053487:DEAD-box RNA Helicases