DOI Page / Citation link:
https://doi.org/10.11588/diglit.48120#0053
Abstracts
35
mobilities ranging from 300 to 50 base pairs. The dot hybridization test for bind-
ing of 32P labelled DNA in SLE IC to DNA from various species showed a bind-
ing to autologous DNA in IC and DNA taken from human hepatoma and HeLa
cells but not from E. coli, salmon nor calf thymus.
From these results, we could find IgG in RA IC and DNA of human origin
in SLE IC as one of their antigenic components.
The Human La Autoantigen Contains an RNA Binding Domain and
an ATP Binding Domain
D. J. Kenan and J. D. Keene
Department of Microbiology and Immunology, Duke University Medical Center, Durham,
NC 27710, USA
Some rheumatologic disorders such as systemic lupus erythematosus and
Sjogren’s syndrome are characterized by the formation of autoantibodies reac-
tive with the La antigen. Biochemical analysis of the La antigen in a wide variety
of vertebrate cells has shown it to be a ribunucleprotein (RNP) complex consisting
of a 48000 Dalton phosphoprotein, termed La, associated with any of the precur-
sor transcripts produced by RNA polymerase III, including pre-tRNA and pre-5S
RNA. Gottlieb and Steitz (EMBO J. 8, 841-861, 1989) have demonstrated
that La protein associates with RNA polymerase III transcription complexes and
that termination of transcription is impaired in the absence of La.
The human La cDNA was cloned using La-specific patient serum as a probe
(Chambers et al., J. Biol. Chem. 263:18043 — 18051, 1988), and the cDNA was
expressed in several prokaryotic systems and in rabbit reticulocyte lysates. cDNA-
encoded protein produced in these systems retained RNA binding specificity iden-
tical to that of HeLa La protein as assayed by RNP immunoprecipitation and by
gel shift analysis. A 76 amino acid sequence was noted in the second quarter of
the La protein sequence that matched the consensus RNA recognition motif
(RRM) as defined by Query et al. (Cell 57:89-101, 1989). A 131 residue trun-
cated La protein, produced in E. coli and containing the RRM, retained the ability
to interact with precursor RNA polymerase III transcripts. These findings are
consistent with the hypothesis that the RRM constitutes part of an RNA binding
domain in La as well as in other RRM proteins.
Near the C-terminus of the conceptual La protein sequence are found two
tandem consensus ATP binding motifs. UV crosslinking experiments using La
35
mobilities ranging from 300 to 50 base pairs. The dot hybridization test for bind-
ing of 32P labelled DNA in SLE IC to DNA from various species showed a bind-
ing to autologous DNA in IC and DNA taken from human hepatoma and HeLa
cells but not from E. coli, salmon nor calf thymus.
From these results, we could find IgG in RA IC and DNA of human origin
in SLE IC as one of their antigenic components.
The Human La Autoantigen Contains an RNA Binding Domain and
an ATP Binding Domain
D. J. Kenan and J. D. Keene
Department of Microbiology and Immunology, Duke University Medical Center, Durham,
NC 27710, USA
Some rheumatologic disorders such as systemic lupus erythematosus and
Sjogren’s syndrome are characterized by the formation of autoantibodies reac-
tive with the La antigen. Biochemical analysis of the La antigen in a wide variety
of vertebrate cells has shown it to be a ribunucleprotein (RNP) complex consisting
of a 48000 Dalton phosphoprotein, termed La, associated with any of the precur-
sor transcripts produced by RNA polymerase III, including pre-tRNA and pre-5S
RNA. Gottlieb and Steitz (EMBO J. 8, 841-861, 1989) have demonstrated
that La protein associates with RNA polymerase III transcription complexes and
that termination of transcription is impaired in the absence of La.
The human La cDNA was cloned using La-specific patient serum as a probe
(Chambers et al., J. Biol. Chem. 263:18043 — 18051, 1988), and the cDNA was
expressed in several prokaryotic systems and in rabbit reticulocyte lysates. cDNA-
encoded protein produced in these systems retained RNA binding specificity iden-
tical to that of HeLa La protein as assayed by RNP immunoprecipitation and by
gel shift analysis. A 76 amino acid sequence was noted in the second quarter of
the La protein sequence that matched the consensus RNA recognition motif
(RRM) as defined by Query et al. (Cell 57:89-101, 1989). A 131 residue trun-
cated La protein, produced in E. coli and containing the RRM, retained the ability
to interact with precursor RNA polymerase III transcripts. These findings are
consistent with the hypothesis that the RRM constitutes part of an RNA binding
domain in La as well as in other RRM proteins.
Near the C-terminus of the conceptual La protein sequence are found two
tandem consensus ATP binding motifs. UV crosslinking experiments using La