ABSTRACT
Human Tumor Necrosis Factor and Lymphotoxin are cytotoxic proteins which have similar biological activities and share 30 percent amino acid homology. The single copy genes which encode these proteins share several structural features: each gene is approximately three kilobase pairs in length and is interrupted by three introns. In addition, these genes are closely linked and have been mapped to human chromosome 6. However, only the last exons of both genes, which code for more than 80 percent of each secreted protein, are significantly homologous (56 percent).
Subject(s)
Cloning, Molecular , Genes , Glycoproteins/genetics , Growth Inhibitors/genetics , Lymphotoxin-alpha/genetics , Amino Acid Sequence , Bacteriophage lambda/genetics , Base Sequence , Chromosomes, Human , DNA/metabolism , DNA Restriction Enzymes , Humans , Sequence Homology, Nucleic Acid , Tumor Necrosis Factor-alphaABSTRACT
We have isolated, sequenced, and determined the chromosomal localization of the gene encoding human lymphotoxin (LT). The single copy gene was isolated from a human genomic library using a 32P-labeled 116 bp synthetic DNA fragment whose sequence was based on the NH2-terminal amino acid sequence of LT. The gene spans 3 kb of DNA and is interrupted by three intervening sequences. The LT gene is located on human chromosome 6, as determined by Southern blot analysis of human-murine hybrid DNA. Putative transcriptional control regions and areas of homology with the promoters of interferon and other genes are identified.
