The complete nucleotide sequences of two different subtypes (adr and adw) of hepatitis B virus (HBV) DNA cloned in E. coli were determined. The sequence of the viral genome of the adr clone was 3188 nucleotides long, and that of the adw clone was 3200 nucleotides long. The adr and adw clones differed from the reported cloned ayw HBV DNA (3182 nucleotides long) in 11.2% and 10.0% of nucleotides, respectively. Heterogeneity of the HBV genome in the clones with the same subtype was observed.

Betacellulin, a member of the epidermal growth factor family, has been identified in the conditioned medium of cell lines derived from mouse pancreatic beta cell tumors. Betacellulin is a 32-kilodalton glycoprotein that appears to be processed from a larger transmembrane precursor by proteolytic cleavage. The carboxyl-terminal domain of betacellulin has 50 percent sequence similarity with that of rat transforming growth factor alpha. Betacellulin is a potent mitogen for retinal pigment epithelial cells and vascular smooth muscle cells.

SummaryPreviously we showed that motility-rehted protein (MRP-1) is an antigen recognized by monoclonal antibody (mAb) M31-15 inhibiting cell motility and that the sequence of MKP-1 coincides with that of CD9. In the present study, plasmid was constructed in which human MRP-1/CD9 cDNA is expressed under the control of the Abelson routine leukemia virus promoter sequence. The expression plasmid for MRP-1/CD9 was introduced into Chinese hamster ovary cells, human lung adenocarcinoma cell line MAC10 (MKP-1 positive), and human myeloma cell line ARH77 (MRP-1 negative). All of the MRP-1/CD9 (over)expressing clones obtained from these transfected cells showed suppressed cell motility (penetration and phagokinetic track assays) depending on the degree of expression of MRP-1/CD9. Overexpression of MRP-1/CD9 by MAC10 cells resulted in the suppression of cell motility (maximally 73%) associated with considerable inhibition of the cell growth (maximally 48%). However, the inhibition of the growth of MAC10 cells by mAb M31-15 was <17% at an antibody concentration of 1-5 #g/m1, which inhibits cell motility by >90%. These results suggest that MRP-1/CD9 directly regulates cell motility and may also affect ceU growth. Effects on metastasis by the expression of MRP-1/CD9 were investigated with mouse melanoma BL6 ceLls-~S, LB/c nu/nu mouse system. Metastatic potential of all transformants expressing MRP-1/CD9 was lower than that of parent BL6 cells.

The expression of human basic fibroblast growth factor (bFGF) cDNA in mouse BALB/c 3T3 clone A31 cells induced morphological transformation. These transformed cells grew well and reached more than a sixfold-higher saturation density than parental A31 cells even in serum-free medium. They were able to form colonies in soft agar. The phenotypic alteration in the transformed cells was reversed by the addition of anti-human bFGF antibodies to the medium. These results suggest that the cellular transformation mediated by bFGF is caused by autocrine stimulation with secreted bFGF molecules.

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