Use of horseradish peroxidase- and fluorescein-modified cisplatin derivatives for simultaneous labeling of nucleic acids and proteins.
BACKGROUND
Microarray platforms will change immunochemical and nucleic acid-based analysis of cell homogenates and body fluids compared with classic analyses. Microarrays use labeled target and immobilized probes, rather than fixed targets and labeled probes. We describe a method for simultaneous labeling of nucleic acids and proteins.


METHODS
Horseradish peroxidase- and fluorescein-modified cisplatin derivatives were used for labeling of nucleic acids and proteins. These reagents, called the Universal Linkage System (ULS), bind to sulfur- and nitrogen-donor ligands present in amino acids and nucleotides. For automated screening of proteins and nucleic acids on microarrays, it is advantageous to label these biomolecules without pre- or postpurification procedures. The labeling of antibodies and nucleic acids in whole serum was therefore pursued.


RESULTS
Immunoglobulins in nonpurified serum were labeled efficiently enough to be used for immunochemistry. To investigate whether protein-adapted labeling allowed nucleic acid labeling as well, 1 microg of plasmid DNA was added to 1 microL of serum. DNA and serum proteins were simultaneously labeled, and this labeled DNA could be used as a probe for direct fluorescence in situ hybridization.


CONCLUSIONS
ULS provides a direct labeling tool for the (simultaneous) modification of proteins and nucleic acids even in unpurified samples.
van Gijlswijk
Rob P M
RP
Kreatech Biotechnology, Vlierweg 20, 1032 LG Amsterdam, The Netherlands.
Talman
Eduard G
EG
Peekel
Inge
I
Bloem
Judith
J
van Velzen
Marcel A
MA
Heetebrij
Rob J
RJ
Tanke
Hans J
HJ
D000818:Animals; D002945:Cisplatin / Q000031:analogs & derivatives* / Q000737:chemistry*; D004247:DNA / Q000097:blood / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay; D005452:Fluoresceins / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006041:Goats; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000737:chemistry; D007075:Immunoglobulin M / Q000097:blood / Q000737:chemistry; D017404:In Situ Hybridization, Fluorescence; D007202:Indicators and Reagents; D010957:Plasmids / Q000097:blood / Q000737:chemistry; D011506:Proteins / Q000032:analysis / Q000737:chemistry*
D005452:Fluoresceins; D005456:Fluorescent Dyes; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007202:Indicators and Reagents; D011506:Proteins; D004247:DNA; D006735:Horseradish Peroxidase; D002945:Cisplatin