ABSTRACT
The primary structure of the protein tyrosine kinase domain of the human met gene has been determined from cDNA clones prepared from transcripts of the activated human met gene. These analyses reveal that the met kinase domain (located on human chromosome 7) possesses unique features that distinguish met from other members of the src family of protein tyrosine kinases. The results also demonstrate that the product of the activated met gene is a fusion protein and that the amino terminal end of this fusion protein, which is encoded by human chromosome 1, exhibits homology to laminin B1.
Subject(s)
Protein-Tyrosine Kinases , Proto-Oncogene Proteins , Amino Acid Sequence , Base Sequence , Chromosomes, Human, Pair 1 , Chromosomes, Human, Pair 7 , Cloning, Molecular , DNA/genetics , Humans , Laminin/genetics , Molecular Sequence Data , Protein-Tyrosine Kinases/genetics , Proto-Oncogene Proteins/geneticsABSTRACT
The DNA sequence of cDNA clones prepared from transcripts of the mouse met proto-oncogene reveals that the mouse met gene encodes a 1380 amino acid protein with the characteristics of a growth factor receptor. This protein can be divided into several putative domains, including an intracellular protein tyrosine kinase domain, a transmembrane domain and a 929 amino acid extracellular domain, possessing a potential proteolytic cleavage site with the sequence Lys-Arg-Arg-Lys-Arg-Ser. To gain additional insights into the function of the met protein we have examined the level of met transcripts in tissues of the late-gestation mouse conceptus. Transcription of met was observed in most of the tissues analysed, but the highest levels of met mRNA were detected in the yolk sac, amnion and kidney; no transcripts were detectable in the calvaria. Chromosomal localization using a series of mouse-hamster hybrid cell lines has demonstrated that met is located on mouse chromosome 6.
Subject(s)
Mice/genetics , Proto-Oncogene Proteins/genetics , Proto-Oncogenes , Receptors, Cell Surface/genetics , Amino Acid Sequence , Animals , Base Sequence , Chromosome Mapping , Cloning, Molecular , Growth Substances , Molecular Sequence DataABSTRACT
This paper describes a so-called ternary transformation system for plant cells. We demonstrate that Agrobacterium tumefaciens strain LBA4404 supplemented with a constitutive virG mutant gene (virGN54D) on a compatible plasmid is capable of very efficient T-DNA transfer to a diverse range of plant species. For the plant species Catharanthus roseus it is shown that increased T-DNA transfer results in increased stable transformation frequencies. Analysis of stably transformed C. roseus cell lines showed that, although the T-DNA transfer frequency is greatly enhanced by addition of virGN54D, only one or a few T-DNA copies are stably integrated into the plant genome. Thus, high transformation frequencies of different plant species can be achieved by introduction of a ternary plasmid carrying a constitutive virG mutant into existing A. tumefaciens strains in combination with standard binary vectors.