Work in our laboratory has focused on the somatic cell genetics and molecular biology of cell surface antigens. In the past year, we have continued our analysis on the mutants that we have been studying for several years. In terms of the continuing studies on the H-2 antigen mutants, we are in the process of analyzing mutants that have undergone structural alterations in a particular H-2 antigen. We have constructed cDNA libraries from such mutants and are in the process of screening these libraries for the mRNA coded for by the mutant gene. We have also initiated two related projects. One involves the relationship between the expression of beta?2?-microglobulin and the H-2 antigens. We have observed and are analyzing two interesting mutant cell lines that fail to express H-2 antigens and/or beta?2?-microglobulin. In one of these mutants, EL/4Mar, the defect appears to be in the H-2K?b? genes, which are not transcribed. In the other cell line, which we call ABM3, the beta?2?-microglobulin genes are present and transcribed but apparently are not translated. The conclusion we have been able to draw from our studies on these two mutant cell lines is that the interaction between beta?2?-microglobulin and H-2 antigens is intricate and defects in the synthesis and expression of either one can result in the failure of the bimolecular complex of H-2 antigens and beta?2?-microglobulin to appear on the cell surface. The other project we have initiated is to study the somatic cell genetics of beta?2?-microglobulin. We have been using two cell lines, R8 and 439.4.2, both of which are heterozygous at the B2m locus. Using a monoclonal directed against the product of the B2m?b? allele, we have isolated a series of mutants that do not express this antigen. The mechanism by which the expression of this antigen is lost in these two cell lines is entirely different. In one cell line, R8, we find that the loss of expression of B2m is due to point mutations in the gene. In the other cell line, 439.4.2, the loss of expression is due to deletions in the gene. All the deletions appear to begin at precisely the same position, and proceed in the 5' direction, resulting in the deletion of the first exon and the promoter. We are attempting to determine the reason for this difference between these two cell lines in the genetic alterations that occur in the B2m gene. (CS)

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA029194-05
Application #
3168567
Study Section
Immunobiology Study Section (IMB)
Project Start
1981-02-01
Project End
1986-02-28
Budget Start
1985-02-01
Budget End
1986-02-28
Support Year
5
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Albert Einstein College of Medicine
Department
Type
Schools of Medicine
DUNS #
009095365
City
Bronx
State
NY
Country
United States
Zip Code
10461
Werner, C; Rajan, T V (1992) Characterization of a myosin heavy chain gene from Brugia malayi. Mol Biochem Parasitol 50:261-8
Werner, C; Rajan, T V (1992) Comparison of the body wall myosin heavy chain sequences from Onchocerca volvulus and Brugia malayi. Mol Biochem Parasitol 50:255-60
Rothstein, N; Rajan, T V (1991) Characterization of an hsp70 gene from the human filarial parasite, Brugia malayi (Nematoda). Mol Biochem Parasitol 49:229-37
Rajan, T V; Moffat, L F; Frankel, W N (1990) Rate and mechanism of generation of beta 2-microglobulin mutants from a heterozygous murine cell line. J Immunol 145:1598-602
Rajan, T V (1990) Molecular biology of human lymphatic filariasis. Exp Parasitol 70:500-3
Nelson, F K; Frankel, W; Rajan, T V (1989) Mitotic recombination is responsible for the loss of heterozygosity in cultured murine cell lines. Mol Cell Biol 9:1284-8
Werner, C; Higashi, G I; Yates, J A et al. (1989) Differential recognition of two cloned Brugia malayi antigens by antibody class. Mol Biochem Parasitol 35:209-18
Frankel, W N; Potter, T A; Rajan, T V (1989) Effect of proviral insertion on transcription of the murine B2mb gene. J Virol 63:2623-8
Cameron, M L; Levy, P; Nutman, T et al. (1988) Use of restriction fragment length polymorphisms (RFLPs) to distinguish between nematodes of pathogenic significance. Parasitology 96 ( Pt 2):381-90
Rothstein, N; Stoller, T J; Rajan, T V (1988) DNA base composition of filarial nematodes. Parasitology 97 ( Pt 1):75-9

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