Nucleic Acids Research, 2003, Vol. 31, No. 2 602-607
© 2003 Oxford University Press
Human RNase 7: a new cationic ribonuclease of the RNase A superfamily
Department of Ecology and Evolutionary Biology, University of Michigan, 3003 Natural Science Building, 830 North University Avenue, Ann Arbor, MI 48109, USA 1 Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
*To whom correspondence should be addressed. Tel: +1 734 763 0527; Fax: +1 734 763 0544; Email: jianzhi{at}umich.edu
Here we report on the expression and function of RNase 7, one of the final RNase A superfamily ribonucleases identified in the human genome sequence. The human RNase 7 gene is expressed in various somatic tissues including the liver, kidney, skeletal muscle and heart. Recombinant RNase 7 is ribonucleolytically active against yeast tRNA, as expected from the presence of eight conserved cysteines and the catalytic histidine–lysine– histidine triad which are signature motifs of this superfamily. The protein is atypically cationic with an isoelectric point (pI) of 10.5. Expression of recombinant RNase 7 in Escherichia coli completely inhibits the growth of the host bacteria, similar to what has been observed for the cationic RNase, eosinophil cationic protein (ECP/RNase 3, pI 11.4). An in vitro assay demonstrates dose-dependent cytotoxicity of RNase 7 against bacteria E.coli, Pseudomonas aeruginosa and Staphylococcus aureus. While RNase 7 and ECP/RNase 3 are both cationic and share this particular aspect of functional similarity, their protein sequence identity is only 40%. Of particular interest, ECP/RNase 3’s cationicity is based on an (over)abundance of arginine residues, whereas RNase 7 includes an excess of lysine. This difference, in conjunction with the independent origins and different expression patterns, suggests that RNase 7 and ECP/RNase 3 may have been recruited to target different pathogens in vivo, if their physiological functions are indeed host defenses.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  H. F. Rosenberg RNase A ribonucleases and host defense: an evolving story J. Leukoc. Biol., May 1, 2008; 83(5): 1079 - 1087. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Harder, R. Glaser, and J.-M. Schroder Review: Human antimicrobial proteins effectors of innate immunity Innate Immunity, December 1, 2007; 13(6): 317 - 338. [Abstract] [PDF]
|
|
|
|
 |
|
 M.-a. I. Economopoulou, E. G. Fragoulis, and D. C. Sideris Molecular cloning and characterization of the human RNase {kappa}, an ortholog of Cc RNase Nucleic Acids Res., October 8, 2007; 35(19): 6389 - 6398. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Cho and J. Zhang Zebrafish Ribonucleases Are Bactericidal: Implications for the Origin of the Vertebrate RNase A Superfamily Mol. Biol. Evol., May 1, 2007; 24(5): 1259 - 1268. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y.-C. Huang, Y.-M. Lin, T.-W. Chang, S.-J. Wu, Y.-S. Lee, M. D.-T. Chang, C. Chen, S.-H. Wu, and Y.-D. Liao The Flexible and Clustered Lysine Residues of Human Ribonuclease 7 Are Critical for Membrane Permeability and Antimicrobial Activity J. Biol. Chem., February 16, 2007; 282(7): 4626 - 4633. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Zhang Disulfide-Bond Reshuffling in the Evolution of an Ape Placental Ribonuclease Mol. Biol. Evol., February 1, 2007; 24(2): 505 - 512. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C.-F. Zhu, Q. Liu, L. Zhang, H.-X. Yuan, W. Zhen, J.-S. Zhang, Z.-J. Chen, S. H. Hall, F. S. French, and Y.-L. Zhang RNase9, an Androgen-Dependent Member of the RNase A Family, Is Specifically Expressed in the Rat Epididymis Biol Reprod, January 1, 2007; 76(1): 63 - 73. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Rudolph, R. Podschun, H. Sahly, S. Schubert, J. M. Schroder, and J. Harder Identification of RNase 8 as a Novel Human Antimicrobial Protein. Antimicrob. Agents Chemother., September 1, 2006; 50(9): 3194 - 3196. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Nitto, K. D. Dyer, M. Czapiga, and H. F. Rosenberg Evolution and Function of Leukocyte RNase A Ribonucleases of the Avian Species, Gallus gallus J. Biol. Chem., September 1, 2006; 281(35): 25622 - 25634. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Castella, H. Benedetti, R. de Llorens, J.-L. Dacheux, and F. Dacheux Train A, an RNase A-Like Protein Without RNase Activity, Is Secreted and Reabsorbed by the Same Epididymal Cells under Testicular Control Biol Reprod, November 1, 2004; 71(5): 1677 - 1687. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. N. Rampias, D. C. Sideris, and E. G. Fragoulis Cc RNase: the Ceratitis capitata ortholog of a novel highly conserved protein family in metazoans Nucleic Acids Res., June 15, 2003; 31(12): 3092 - 3100. [Abstract] [Full Text] [PDF]
|
|