Abstracts
17
The longest cDNA clone (FR68) was about 1.7 kb in length which corresponded
to the length of the band obtained in the Northern blot analysis using HeLa cell
RNA. The cDNA was subcloned into a plasmid expression vector pEX-3 and
positive clones were screened using anti-RNP positive patients’ sera. The recombi-
nant plasmid (FR68EX) expressed a fusion protein with cro-/Lgalactosidase
whose molecular weight was estimated to be about 170kDa. To determine the
epitope(s), many in-frame deletion mutants were produced using restriction sites
within cDNA or by digestion with exonuclease III. The resultant fusion proteins
were partially purified and applied for the enzyme linked immunosorbent assay’
(ELISA). Three-fourth of conventionally determined anti-RNP positive sera were
shown to be positive.
The cDNA clone FR68EX contains an insert of 1.7 kb which is identical with
the 3' terminal half of FL70K (Theissen et al. EMBO J. 1986) and contains a
probable initiation codon located at 1212 of FL70K, which is consistent with
Spritz’ argument that the initiation codon of the functional mRNA of the 68 k
protein is not located at nucleotide position 681 but at 1212 (NAR. 1987). Dele-
tion mutants of FR68EX express fusion proteins with different molecular weights
ranging from 116 kDa (cro-/Lgalactosidase) to 170 kDa (FR68EX), which were
stained with several anti-RNP positive sera. Deletion mutants which contain more
than 600 bp from the initiation codon show comparably positive staining to that
obtained with FR68EX, but a deletion mutant which contains only 5'-terminal
150 bp shows negative staining. Thus, we tentatively concluded that at least one
of the major epitopes resides between nucleotide positions 1363 and 1803. This
region contains a nucleotide sequence encoding amino acids homologous to that
of murine leukemia virus group-specific antigen p30gag (Keene et al. Cell. 1987).
Molecular Characterization of the PM/SCL Antigen
C. Gelpi, A. Alguero, Ma. A. Martinez, S. Vidal, C. Juarez,
and J. L. Rodriguez-Sanchez
Hospital de la Santa Creu i Sant Pau, Hospital Universitari de la Facultat de Medicina de
la Universitat Autonoma de Barcelona, San Antonio Ma. Claret, 167, 08025 Barcelona,
Spain
In the 117 sera study of patients with progressive systemic scleroderma (72)
polimyositis (12) and sclero-polimyositis (23), 12 precipitated a macromolecular
complex of 13 polypeptides, whose aproximate molecular weights were: 110, 90,
17
The longest cDNA clone (FR68) was about 1.7 kb in length which corresponded
to the length of the band obtained in the Northern blot analysis using HeLa cell
RNA. The cDNA was subcloned into a plasmid expression vector pEX-3 and
positive clones were screened using anti-RNP positive patients’ sera. The recombi-
nant plasmid (FR68EX) expressed a fusion protein with cro-/Lgalactosidase
whose molecular weight was estimated to be about 170kDa. To determine the
epitope(s), many in-frame deletion mutants were produced using restriction sites
within cDNA or by digestion with exonuclease III. The resultant fusion proteins
were partially purified and applied for the enzyme linked immunosorbent assay’
(ELISA). Three-fourth of conventionally determined anti-RNP positive sera were
shown to be positive.
The cDNA clone FR68EX contains an insert of 1.7 kb which is identical with
the 3' terminal half of FL70K (Theissen et al. EMBO J. 1986) and contains a
probable initiation codon located at 1212 of FL70K, which is consistent with
Spritz’ argument that the initiation codon of the functional mRNA of the 68 k
protein is not located at nucleotide position 681 but at 1212 (NAR. 1987). Dele-
tion mutants of FR68EX express fusion proteins with different molecular weights
ranging from 116 kDa (cro-/Lgalactosidase) to 170 kDa (FR68EX), which were
stained with several anti-RNP positive sera. Deletion mutants which contain more
than 600 bp from the initiation codon show comparably positive staining to that
obtained with FR68EX, but a deletion mutant which contains only 5'-terminal
150 bp shows negative staining. Thus, we tentatively concluded that at least one
of the major epitopes resides between nucleotide positions 1363 and 1803. This
region contains a nucleotide sequence encoding amino acids homologous to that
of murine leukemia virus group-specific antigen p30gag (Keene et al. Cell. 1987).
Molecular Characterization of the PM/SCL Antigen
C. Gelpi, A. Alguero, Ma. A. Martinez, S. Vidal, C. Juarez,
and J. L. Rodriguez-Sanchez
Hospital de la Santa Creu i Sant Pau, Hospital Universitari de la Facultat de Medicina de
la Universitat Autonoma de Barcelona, San Antonio Ma. Claret, 167, 08025 Barcelona,
Spain
In the 117 sera study of patients with progressive systemic scleroderma (72)
polimyositis (12) and sclero-polimyositis (23), 12 precipitated a macromolecular
complex of 13 polypeptides, whose aproximate molecular weights were: 110, 90,