Basement membrane components are key players in specialized extracellular matrices

More than three decades ago, basement membranes (BMs) were described as membrane-like structures capable of isolating a cell from and connecting a cell to its environment. Since this time, it has been revealed that BMs are specialized extracellular matrices (sECMs) with unique components that support important functions including differentiation, proliferation, migration, and chemotaxis of cells during development. The composition of these sECM is as unique as the tissues to which they are localized, opening the possibility that such matrices can fulfill distinct functions. Changes in BM composition play significant roles in facilitating the development of various diseases. Furthermore, tissues have to provide sECM for their stem cells during development and for their adult life. Here, we briefly review the latest research on these unique sECM and their components with a special emphasis on embryonic and adult stem cells and their niches

A large-scale mutation search reveals genetic heterogeneity in 3M syndrome

The 3M syndrome is a rare autosomal recessive disorder recently ascribed to mutations in the CUL7 gene and characterized by severe pre- and postnatal growth retardation. Studying a series of 33 novel cases of 3M syndrome, we have identified deleterious CUL7 mutations in 23/33 patients, including 19 novel mutations and one paternal isodisomy of chromosome 6 encompassing a CUL7 mutation. Lack of mutations in 10/33 cases and exclusion of the CUL7 locus on chromosome 6p21.1 in six consanguineous families strongly support the genetic heterogeneity of the 3M syndrome

Assemblage variability and bifacial points in the lowermost Sibudan layers at Sibudu, South Africa

Building on the important work of Lyn Wadley at Sibudu, archeologists from the University of Tübingen have excavated the upper stratigraphic units of the Middle Stone Age (MSA) sequence down to the Howiesons Poort (HP). Here, we present the main results from lithic analyses of the lowest part of the Sibudan sequence to assess its overall variability and taxonomic status. Based on the new findings, we also discuss the implications for archeological systematics and the cultural evolution of modern humans in MIS 3 from a more general perspective. The Sibudan deposits encompass over 20 archeological horizons that span a 1.2-m-thick, well-stratified sequence whose base and top have been dated to ∼58 ka (MIS 3). In contrast to the upper stratigraphic units, the lower Sibudan assemblages that we analyzed here show much higher use of local sandstone, quartz, and quartzite. These older units are characterized by frequent use of expedient core reduction methods, bipolar reduction of locally available quartz and quartzite, less retouch of blanks, and lower find densities. Tongati and Ndwedwe tools, which feature abundantly in the upper part of the Sibudan sequence, are entirely absent, as are unifacial points. Instead, notched and denticulated tools are common. Surprisingly, knappers manufactured small bifacial points, mainly made from quartz, by means of alternating shaping in the course of the oldest occupations. The results highlight the great diversity of human technological behavior over even short periods during the MSA, raising important questions about the mechanisms of behavioral change, cultural taxonomy, appropriate scales of lithic analyses, and the relationship between the HP and the Sibudan. Our findings further erode the old idea that bifacial technology in southern Africa is limited to the Still Bay. Research is increasingly showing that bifacial points come and go in different forms and contexts of African Late Pleistocene technology, impeding their use as chrono-cultural markers