Biomedical subjects

B Pepinsky

Publications and source records attributed to B Pepinsky.

3 recordsLinked to original sources

PubMed1992

Structure/function studies on vascular cell adhesion molecule-1.

Vascular cell adhesion molecule-1 (VCAM1) is a member of the immunoglobulin (Ig) superfamily which interacts with the integrin very late antigen-4 (VLA4). The VCAM1/VLA4 interaction mediates both adhesion and signal transduction and is thought to play an important role in inflammatory and immune responses in vivo. The major form of human VCAM1 contains seven extracellular Ig-like domains, with domain 1 designated as the most N-terminal. We have examined the relationship between human VCAM1 structure and function using a combination of domain truncation mutants and proteolytic fragmentation of recombinant soluble VCAM1. We have characterized two regions of VCAM1, localized to domains 4 and 5, which are highly sensitive to proteolytic cleavage, localized the epitope of the blocking monoclonal antibody 4B9 to domain 1, and found that domains 1-3 are sufficient for both its adhesive function and its ability to initiate T cell activation.

Amino Acid Sequence↗

PubMed1991

Cooperative binding of the E2 protein of bovine papillomavirus to adjacent E2-responsive sequences.

The DNA-binding properties of purified full-length E2 protein from bovine papillomavirus type 1 have been investigated by utilizing a quantitative gel shift analysis. By using a recombinant baculovirus which express the E2 open reading frame from the polyhedrin promoter, the full-length E2 protein was synthesized in insect cells and purified to homogeneity by using an E2 binding site (ACCGN4CGGT)-specific oligonucleotide column. The Kd of E2 binding to a 41-bp oligonucleotide containing a single binding site was found to be 2 x 10(-11) M. When two binding sites were included on an oligonucleotide, cooperative binding to these sites by the E2 protein was observed. A cooperativity parameter of 8.5 was determined for E2 binding to two sites. An 86-amino-acid peptide encompassing the C terminus of the protein retains the ability to bind E2 binding sites with a Kd of 4 x 10(-10) M but exhibits slight cooperativity of binding to two adjacent sites. A major determinant for cooperative binding of the full-length E2 protein is thus encoded by the N-terminal amino acids outside the minimal DNA binding domain.

Baculoviridae↗

PubMed1989

Minimal antiproliferative effect of recombinant müllerian inhibiting substance on gynecological tumor cell lines and tumor explants.

Múllerian Inhibiting Substance (MIS) is a testicular hormone that promotes involution of the Múllerian duct during embryogenesis. The Múllerian duct gives rise to adult female reproductive ducts including the fallopian tubes, uterus, and upper vagina. Thus, testicular MIS ensures the regression of female sex organ primordia. Partially purified bovine MIS was reported to inhibit proliferation of tumor cells derived from human gynecological cancers. These observations suggest that MIS might be an effective anticancer agent for some human tumors. Recombinant human MIS (rHu-MIS) has recently become available. To assess the antiproliferative activity of rHu-MIS, we examined its effects on 11 ovarian, six endometrial, and two nongynecological human tumor cell lines. rHu-MIS had no effect on proliferation of these cell lines in five independent assays. Forty-three primary human tumor explants were also examined in human tumor colony forming assays, gel-supported primary culture assays, and subrenal capsule assays. rHu-MIS significantly inhibited the growth of five of these tumors including four ovarian and one small cell lung cancer explant. The four ovarian cancer responses include three of 13 (23%) explants tested in human tumor colony-forming assays and one of eight (12.5%) explants tested in gel-supported primary culture assays. We conclude that rHu-MIS may have antiproliferative activity against some human ovarian cancers.

Animals↗