Abstract
We isolated two cDNA clones encoding human proteins which interact with DNA helicase Q1/RecQL, a human homologue of Eschelichia coli RecQ protein, by two-hybrid screening. One of these proteins, named Qip1, was a novel protein homologous to the nuclear localization signal (NLS) receptor importin-alpha, and the other was the known protein Rch1, which is also a homologue of importin-alpha. DNA helicase Q1 in human cell lysates was coprecipitated with bacterially expressed Qip1 and Rch1 fused with glutathione-S-transferase with glutathione Sepharose beads, confirming the interaction between these proteins and DNA helicase Q1. Two-hybrid experiments revealed that Qip1 interacted with the NLS of SV40 T antigen similar to Rch1 and hSrp1. In addition, interaction of the putative NLS in DNA helicase Q1 with Qip1 and Rch1 but not with hSrp1 was confirmed by the two-hybrid system.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / genetics
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Adenosine Triphosphatases / metabolism*
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Amino Acid Sequence
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Blotting, Western
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Carrier Proteins / chemistry
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Carrier Proteins / genetics*
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Carrier Proteins / metabolism*
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Cloning, Molecular
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DNA Helicases / genetics
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DNA Helicases / metabolism*
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Escherichia coli / genetics
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Gene Expression
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Glutathione / metabolism
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Humans
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Karyopherins
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Molecular Sequence Data
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Nuclear Localization Signals
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Nuclear Proteins / chemistry
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Nuclear Proteins / genetics*
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Nuclear Proteins / metabolism*
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Protein Binding
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RecQ Helicases
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Saccharomyces cerevisiae / chemistry
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Sepharose
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Sequence Alignment
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Sequence Analysis
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alpha Karyopherins
Substances
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Carrier Proteins
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KPNA4 protein, human
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Karyopherins
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Nuclear Localization Signals
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Nuclear Proteins
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alpha Karyopherins
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karyopherin alpha 2
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Sepharose
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Adenosine Triphosphatases
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RECQL4 protein, human
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DNA Helicases
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RecQ Helicases
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Glutathione