Search PubMed⌕ Search

Biomedical subjects

J G Frelinger

Publications and source records attributed to J G Frelinger.

62 records · Page 4Linked to original sources
PubMed1981

Serological and biochemical characterization of rat (RT1) class II molecules with restricted mouse anti-Ia sera.

Murine anti-Ia sera were tested for their reactivity with rat peripheral lymphocytes. Extensive cross-reactions were observed in a complement-dependent cytotoxicity assay. In the majority of strain combinations, these reactions were specific for B cells. We demonstrated by absorption analyses that (1) the reaction was specific, (2) B cells from all rat strains reacted with anti-I-Ek serum, and (3) the anti-I-A sera defined five new specificities. These antisera can also immunoprecipitate class II (Ia-like) molecules from radiolabeled, detergent-solubilized cell extracts. The rat equivalents of molecules encoded in the I-A and I-E subregions in mice can be isolated from all rat strains studied. The alpha and beta subunits of the rat class II molecules were polymorphic when analyzed by sodium dodecyl sulfate (SDS) polyacrylamide electrophoresis. This observation allows the characterization of rat alloantisera or monoclonals of unknown specificity by comparing them to the defined reactivity of the mouse anti-Ia sera.

Absorption↗
PubMed1981

A pseudogene homologous to mouse transplantation antigens: transplantation antigens are encoded by eight exons that correlate with protein domains.

We have isolated about 30 to 40 different BALB/c mouse sperm DNA genomic clones that hybridize to cDNA clones encoding proteins homologous to transplantation antigens. One of these clones (27.1) was selected for sequence because it was polymorphic in Southern blot analysis of the DNAs from BALB/c and CBA mice. A fragment of 5.7 kilobases of this clone was completely sequenced and found to contain a pseudogene whose sequence is highly homologous to the sequences of known transplantation antigens. Pseudogene 27.1 is split into eight exons that correlate with the structurally defined protein domains of transplantation antigens. Using Southern blot hybridization on the DNAs of different inbred mouse strains, we mapped the pseudogene to the Qa-2,3 region, a part of the Tla complex on chromosome 17 that is adjacent to the major histocompatibility complex. The Qa2,3 region encodes lymphoid differentiation antigens homologous to the transplantation antigens in size, in peptide map profiles and in their association with beta2-microglobulin. These mapping studies suggest that gene 27.1 may be a pseudogene for eigher a Qa antigen or an as yet undefined transplantation antigen. Accordingly, we may have isolate genes encoding lymphoid differentiation antigens of the Tla complex as well as those encoding transplantation antigens among the 30 to 40 different genomic clones isolated from our sperm library.

Base Sequence↗
PubMed1981

Three cDNA clones encoding mouse transplantation antigens: homology to immunoglobulin genes.

We constructed cDNA libraries from poly(A)+ RNA isolated from cell lines of two different inbred strains of mice, and screened the libraries with a cDNA clone encoding a human transplantation antigen. Three cDNA clones were identified, sequenced and found to encode amino acid sequences highly homologous to portions of a known mouse transplantation antigen. Comparison of the cDNA sequences of mouse transplantation antigens with the constant region domains of the mouse immunoglobulin mu gene reveals a striking homology, which suggests that the two genes share a common ancestor. Antibody genes undergo DNA rearrangement during B cell differentiation that are correlated with their expression. In contrast, DNA blots with these cDNA probes suggest that the genes for the transplantation antigens are not rearranged in the genomes of liver or embryo cells, which express these antigens, as compared with sperm cells, which do not express these antigens. In Bam Hl-digested liver DNAs from different inbred strains of mice, 10-15 bands of hybridization were found. Accordingly, the genes encoding the transplantation antigens appear to constitute a multigene family with similar gene numbers in different mice.

Amino Acid Sequence↗
PubMed1980

Bone marrow origin of Ia molecules purified from epidermal cells.

Using radiation bone marrow chimeras, we have shown that Ia molecules purified from epidermal cell preparations of the mouse reflect the Ia phenotype of the bone marrow donor. This result strongly suggests that Ia molecules are synthesized by a bone-marrow-derived cell in the epidermis. Furthermore, results of peptide map analysis of immunoprecipitated biosynthetically labeled Ia suggest that the Ia molecules found in skin are identical to those found on B lymphocytes. These results support biochemical as well as serologic identity.

Animals↗
PubMed1976

Effects of Chloramphenicol on the Circadian Rhythm of Neurospora crassa.

Chloramphenicol, an inhibitor of mitochondrial protein synthesis, shortened the period length of the circadian rhythm in the Timex strain of Neurospora crassa by 2 hours. Both the l(+) threo and d(-) threo optical isomers had the same effect on the period of the rhythm, whereas only the d(-) threo isomer significantly inhibited mitochondrial protein synthesis. Tetracycline, another inhibitor of mitochondrial protein synthesis, did not change the period of the circadian rhythm. The effect of chloramphenicol on the circadian rhythm is, therefore, presumably not directly related to inhibition of mitochondrial protein synthesis, suggesting that chloramphenicol has other effects.

Journal Article↗