(Table 2) Varimax factor matrix of planktonic foraminifera at DSDP Hole 72-517

Quaternary sediments were recovered at all four Sites at Leg 72. Planktonic foraminifers were abundant and well preserved, especially in the holes shielded from Antarctic Bottom Water (AABW) influence. The fauna belonged to the subtropical province marked by Globigerinoides ruber and to a lesser extent by Globorotalia inflata. Thirty planktonic foraminiferal species were distinguished, and a detailed study of the Site 517 stratigraphy was made. The Quaternary sequence of the Rio Grande Rise was subdivided slightly differently from the Bolli and Premoli Suva (1973) pattern. Five subzones were identified but some difficulties arose when a precise correlation became necessary in the subzones of the tropical provinces. Correlations could nevertheless be made, particularly with respect to the earliest Quaternary. Quaternary faunal data have been dated by isotopic stratigraphy (Vergnaud Grazzini et al.,1983) and partially contradict results previously published for this part of the Atlantic (Williams and Ledbetter, 1979). By studying the occurrence of planktonic foraminifers, we obtained more information about hydrologic variations during the Quaternary sequence of Hole 517; two broad periods were recognized. Finally, we identified the interaction between the Brazil Current and the subtropical convergence

Functional Hierarchy of Simultaneously Expressed Adhesion Receptors: Integrin α2β1 but Not CD44 Mediates MV3 Melanoma Cell Migration and Matrix Reorganization within Three-dimensional Hyaluronan-containing Collagen MatricesV⃞

Haptokinetic cell migration across surfaces is mediated by adhesion receptors including β1 integrins and CD44 providing adhesion to extracellular matrix (ECM) ligands such as collagen and hyaluronan (HA), respectively. Little is known, however, about how such different receptor systems synergize for cell migration through three-dimensionally (3-D) interconnected ECM ligands. In highly motile human MV3 melanoma cells, both β1 integrins and CD44 are abundantly expressed, support migration across collagen and HA, respectively, and are deposited upon migration, whereas only β1 integrins but not CD44 redistribute to focal adhesions. In 3-D collagen lattices in the presence or absence of HA and cross-linking chondroitin sulfate, MV3 cell migration and associated functions such as polarization and matrix reorganization were blocked by anti-β1 and anti-α2 integrin mAbs, whereas mAbs blocking CD44, α3, α5, α6, or αv integrins showed no effect. With use of highly sensitive time-lapse videomicroscopy and computer-assisted cell tracking techniques, promigratory functions of CD44 were excluded. 1) Addition of HA did not increase the migratory cell population or its migration velocity, 2) blocking of the HA-binding Hermes-1 epitope did not affect migration, and 3) impaired migration after blocking or activation of β1 integrins was not restored via CD44. Because α2β1-mediated migration was neither synergized nor replaced by CD44–HA interactions, we conclude that the biophysical properties of 3-D multicomponent ECM impose more restricted molecular functions of adhesion receptors, thereby differing from haptokinetic migration across surfaces.

Repression of a matrix metalloprotease gene by E1A correlates with its ability to bind to cell type-specific transcription factor AP-2.

Adenovirus E1A 243-amino acid protein can repress a variety of enhancer -linked viral and cellular promoters. This repression is presumed to be mediated by its interaction with and sequestration of p3OO, a transcriptional coactivator. Type IV 72-kDa collagenase is one of the matrix metalloproteases that has been implicated in differentiation, development, angiogenesis, and tumor metastasis. We show here that the cell type-specific transcription factor AP-2 is an important transcription factor for the activation of the type IV 72-kDa collagenase promoter and that adenovirus E1A 243-amino acid protein represses this promoter by targeting AP-2. Glutathione S-transferase-affinity chromatography studies show that the E1A protein interacts with the DNA binding/dimerization region of AP-2 and that the N-terminal amino acids of E1A protein are required for this interaction. Further, E1A deletion mutants which do not bind to p3OO can repress this collagenase promoter as efficiently as the wildtype E1A protein. Because the AP-2 element is present in a variety of viral and cellular enhancers which are repressed by E1A, these studies suggest that E1A protein can repress cellular and viral promoter/enhancers by forming a complex with cellular transcription factors and that this repression mechanism may be independent of its interaction with p3OO.