WO2003088381-A3  UENO Y ET AL: "NUCLEOSIDES AND NUCLEOTIDES. 165. CHEMICAL LIGATION OF OLIGODEOXYNUCLEOTIDES HAVING A MERCAPTO GROUP AT THE 5-POSITION OF 2'-DEOXYURIDINE VIA A DISULFIDE BOND" NUCLEOSIDES & NUCLEOTIDES, MARCEL DEKKER, INC, US, vol. 17, no. 1-3, 1998, pages 283-289, XP001149079 ISSN: 0732-8311;  SHIMKUS M L ET AL: "SYNTHESIS AND CHARACTERIZATION OF BIOTIN-LABELED NUCLEOTIDE ANALOGS" DNA (NEW YORK), vol. 5, no. 3, 1986, pages 247-256, XP009012255 ISSN: 0198-0238;  HERMAN T M ET AL: "CHEMICALLY CLEAVABLE BIOTIN-LABELED NUCLEOTIDE ANALOGS" METHODS IN ENZYMOLOGY, 1990, pages 584-588, XP001152912 ISSN: 0076-6879 cited in the application;  SHIMKUS M ET AL: "A chemically cleavable biotinylated nucleotide: usefulness in the recovery of protein-DNA complexes from avidin affinity columns." PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. UNITED STATES MAY 1985, vol. 82, no. 9, May 1985 (1985-05), pages 2593-2597, XP009012256 ISSN: 0027-8424;  AHMADIAN MOHAMMAD ET AL: "A comparative study of the thermal stability of oligodeoxyribonucleotides containing 5-substituted 2'-deoxyuridines." NUCLEIC ACIDS RESEARCH, vol. 26, no. 13, 1 July 1998 (1998-07-01), pages 3127-3135, XP002246216 ISSN: 0305-1048;  LANGER P R ET AL: "ENZYMATIC SYNTHESIS OF BIOTIN-LABELED POLYNUCLEOTIDES: NOVEL NUCLEID ACID AFFINITY PROBES" PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES, NATIONAL ACADEMY OF SCIENCE, WASHINGTON, DC, US, vol. 78, no. 11, November 1981 (1981-11), pages 6633-6637, XP000892770 ISSN: 0027-8424;  LOMANT A J ET AL: "Chemical probes of extended biological structures: synthesis and properties of the cleavable protein cross-linking reagent [35SUedithiobis(succinimidyl propionate)." JOURNAL OF MOLECULAR BIOLOGY. ENGLAND 14 JUN 1976, vol. 104, no. 1, 14 June 1976 (1976-06-14), pages 243-261, XP009012241 ISSN: 0022-2836 cited in the application;  SOUKUP G A ET AL: "Preparation of oligonucleotide-biotin conjugates with cleavable linkers." BIOCONJUGATE CHEMISTRY. UNITED STATES 1995 JAN-FEB, vol. 6, no. 1, January 1995 (1995-01), pages 135-138, XP002246344 ISSN: 1043-1802