Biomedical subjects

L J Baier

Publications and source records attributed to L J Baier.

25 records · Page 2Linked to original sources

PubMed1993

The mouse antiphosphotyrosine immunoreactive kinase, TIK, is indistinguishable from the double-stranded RNA-dependent, interferon-induced protein kinase, PKR.

The mouse TIK protein, a serine/threonine kinase, was originally isolated from a murine pre-B cell expression library by its ability to bind anti-phosphotyrosine antibodies (Icely et al., J. Biol. Chem. 266, 16073-16077, 1991). The 67 kDa protein was found to have an associated autophosphorylation activity when incubated with ATP. Our results show that TIK is actually the mouse interferon-induced, dsRNA-dependent protein kinase, PKR. We demonstrate that the TIK message is interferon-inducible in mouse L-cells and in vitro transcription and translation of the TIK cDNA produces a protein that is capable of binding double-stranded RNA. The in vitro synthesized TIK protein migrated as a 65 kDa protein on SDS-PAGE when incubated with ATP, but migrated as a 60 kDa protein when incubated with an inhibitor of PKR, 2-aminopurine. We further show that proteolytic digestion of TIK with Staphylococcus aureus V8 protease results in a cleavage pattern identical to that obtained by V8 digestion of authentic PKR. Antiserum to TIK specifically recognized PKR. Cloned TIK had inhibitory activity for replication of EMCV but not VSV. From these observations we conclude that TIK kinase is the mouse interferon-induced, double-stranded RNA-dependent kinase, PKR.

Adenosine Triphosphate↗

PubMed1991

Lymphoid expression and TATAA binding of a human protein containing an Antennapedia homeodomain.

In an effort to identify human proteins that bind to the TATAA box, a lambda gt-11 expression library was screened with a radiolabeled DNA probe containing 12 copies of the TATAA sequence. A cDNA encoding a specific TATAA binding protein was isolated and found to contain a homeobox domain identical at 59 of 60 residues to the Drosophila Antennapedia (Antp) homeodomain, as well as another conserved motif found in homeotic genes, the homeo-specific pentapeptide. Although this and other Antp-like homeobox proteins have been described previously in neuronal cells and fibroblasts, we report the expression of this gene in lymphoid cells. This cDNA, isolated from a B-cell library, hybridizes to a 1.6-kb messenger RNA in several T- and B-cell lines, and the expected protein was identified in Jurkat T-lymphoid cells by Western blot analysis. The DNA binding specificity of this human Antp clone was analyzed using single-base mutations of the TATAA sequence. The first thymidine, as well as the last three bases (TAA), were important for homeobox binding. Finally, the function of the highly conserved homeospecific pentapeptide protein region was investigated in both the human and Drosophila Antp proteins. The homeospecific pentapeptide region was not required for DNA binding, and Drosophila Antp proteins mutated in the pentapeptide region were able to transactivate the Ubx promoter in Schneider L2 cells, in contrast to a homeodomain mutation, suggesting an alternative function for the homeospecific pentapeptide in homeotic genes. Because the human Antp TATAA binding protein is expressed in both lymphoid and non-lymphoid cells, we suggest that this homeobox gene has evolved a more general transcriptional regulatory function in higher eukaryotic cells.

Amino Acid Sequence↗

PubMed1986

Two-dimensional gel electrophoresis of cellular proteins reveals myeloid origin of blasts in two children with otherwise undifferentiated leukemia.

In previous studies, two-dimensional polyacrylamide gel electrophoresis allowed the detection of 11 polypeptide markers that distinguished between subtypes of acute lymphoblastic leukemia and between acute lymphoblastic and acute myelocytic leukemia. This report describes the occurrence of polypeptide markers in two-dimensional gels that indicate a myeloid origin of blasts obtained from two children who presented with acute leukemia, the cells of origin of which could not be determined, at the time of diagnosis, by morphologic, cytochemical, or immune marker analysis. The authors conclude that two-dimensional electrophoresis provides a new tool for the delineation of the cell of origin in acute leukemia.

Acute Disease↗

PubMed1986

Lineage-related polypeptide markers in acute lymphoblastic leukemia detected by two-dimensional gel electrophoresis.

We have utilized two-dimensional polyacrylamide gel electrophoresis, coupled with ultrasensitive silver staining, to identify lineage-related polypeptide markers in lymphoblasts from children with acute lymphoblastic leukemia. Twelve polypeptides were detected that could distinguish between the major subgroups of acute lymphoblastic leukemia. These included a new marker for common acute lymphoblastic leukemia and markers for cells of B and T lineages. Analysis of the two-dimensional patterns also allowed the tentative identification of T-cell lineage in two cases with an otherwise undifferentiated non-T-cell non-B-cell phenotype. Two-dimensional electrophoresis thus provides a powerful tool for the delineation of the cell of origin in leukemia.

B-Lymphocytes↗

PubMed1986

Genetic variants detected among 106 lymphocyte polypeptides observed in two-dimensional gels.

Peripheral blood lymphocytes from 40 children have been examined for genetic variation in their protein constituents by two-dimensional polyacrylamide gel electrophoresis. One hundred six polypeptides chosen without respect to genetic variability were scored in gels from the 40 children. For each child, gels from both parents were also examined to substantiate the genetic basis of variants observed. Of the total of 4,240 polypeptides, 23 could not be scored unambiguously. Fourteen of the polypeptides showed genetic variants in one or more of the children. One hundred twenty-nine of 4,217 polypeptides scored exhibited the combination of a normal and a variant polypeptide. All variants were present in at least one of the parents of the subject. The index of heterozygosity observed (3.05% +/- .23%) indicates substantial genetic variation in cellular protein constituents.

Adult↗

PubMed1986

Genetic analysis of thirty-three platelet polypeptides detected in two-dimensional polyacrylamide gels.

Two-dimensional gel electrophoresis followed by silver-staining was utilized to visualize platelet polypeptides for genetic analysis. A subset of 33 polypeptides that were most suited for scoring was selected. Families consisting of father-mother-child trios were studied. Thirty-six polypeptides of a total of 1,413 scored in children's gels exhibited the combination of a normal and a variant polypeptide. The observed index of heterozygosity of 2.55% is comparable to our previously reported findings for red cell proteins.

Blood Platelets↗

PubMed1984

Mice homozygous for chromosomal deletions at the albino locus region lack specific polypeptides in two-dimensional gels.

Radiation-induced chromosomal deletions involving the albino locus region of the mouse result, when homozygous, in abnormalities ranging from sterility to lethality at various stages of development. We have utilized two-dimensional electrophoresis to search for polypeptide alterations in livers from newborn mice homozygous for the c14CoS and c3H deletions and also from c3H/c6H compound heterozygote mice. Five-hundred polypeptide spots detectable in normal mouse liver gels were scored. Alterations involving five polypeptides were observed in the various overlapping deletions. A spot corresponding to a polypeptide with a 38,000 Mr was missing from mice homozygous for the short c14CoS and the longer overlapping c3H deletions. Another polypeptide with a 29,000 Mr was missing from c3H homozygotes and c3H/c6H heterozygotes. A third polypeptide with a 62,000 Mr was missing only from c3H homozygotes. Two additional polypeptides were markedly increased in amount in c14CoS and c3H homozygotes. The partial overlap between the three deletions analyzed allows provisional genetic mapping of previously unknown loci for three of the five electrophoretically identifiable polypeptides expressed in newborn mouse livers. The results obtained provide a basis for studying radiation-induced deletions with two-dimensional electrophoresis gels.

Albinism↗