GAS41, a highly conserved protein in eukaryotic nuclei, binds to NuMA.
The yeast two-hybrid system was used to identify binding partners of NuMA, a component of the nuclear matrix in interphase cells. By using the C-terminal half of NuMA as bait, a human cDNA sequence coding for a 223-amino acid protein with a non-helical N-terminal domain and a C-terminal alpha-helical portion was identified and fully sequenced. It was identical to GAS41, a sequence amplified in human gliomas. The sequence of the homologous Drosophila protein was established, and the alignment for GAS41 from nine different species showed that GAS41 is a general eukaryotic protein found in species as diverse as Arabidopsis, Drosophila, Caenorhabditis elegans, yeast, and man. Northern blot analysis showed a single transcript in eight human tissues. A polyclonal antibody to GAS41 showed a dotted staining pattern in interphase nuclei and a uniform distribution in mitotic cells. A GFP-GAS41 fusion protein displayed equivalent patterns. In vitro GAS41 bound to the C-terminal part of the rod region of NuMA, as shown by dot overlay and by surface plasmon resonance measurements. The K(d) of the complex was 2 x 10(-)(7) m. GAS41 is related to the AF-9 and ENL proteins, which are putative transcription factors found as fusion proteins in some acute leukemias. The NuMA/GAS41 interaction may provide a link between nuclear structure and gene expression.
Department of Biochemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen, Germany. jharbor@gwdg.de
J
J
Harborth
K
K
Weber
M
M
Osborn
D000595:Amino Acid Sequence; D000818:Animals; D034961:Antigens, Nuclear; D001483:Base Sequence; D018797:Cell Cycle Proteins; D017124:Conserved Sequence; D005455:Fluorescent Antibody Technique; D020869:Gene Expression Profiling; D006801:Humans; D008938:Mitosis; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D020349:Surface Plasmon Resonance; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques
D034961:Antigens, Nuclear; D018797:Cell Cycle Proteins; C050045:NUMA1 protein, human; D009363:Neoplasm Proteins; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; C109446:YEATS4 protein, human