Anti-KERA (aa 253-351) polyclonal antibody

Keratocan is an extracellular matrix protein that belongs to the small leucine-rich proteoglycan family that also includes lumican, biglycan, decorin, mimecan, and fibromodulin. Members of this family are known to play a role in regulating cellular processes such as proliferation and modulation of osteoprogenitor lineage differentiation. The aims of this study were to evaluate the expression pattern of the keratocan within the osteoprogenitor lineage and to assess its role in regulating osteoblast maturation and function. Results from gene expression analyses of cells at different maturation stages within the osteoblast lineage indicate that keratocan is differentially expressed by osteoblasts and shows little or no expression by osteocytes. During primary osteoblast cultures, high keratocan mRNA expression was observed on day 14, whereas lower expression was detected at days 7 and 21. To assess the effects of keratocan on osteoprogenitor cell differentiation, we evaluated primary calvarial cell cultures from keratocan-deficient mice. The mineralization of calvarial osteoblast cultures derived from keratocan null (Kera-/-) mice was lower than in wild-type osteoblast cultures. Furthermore, analysis of RNA derived from Kera-/- calvarial cell cultures showed a reduction in the mature osteoblast differentiation markers, that is, bone sialoprotein and osteocalcin. In addition, we have evaluated the bone formation in keratocan-deficient mice. Histomorphometric analysis indicated that homozygous knockout mice have significantly decreased rates of bone formation and mineral apposition. Taken together, our results demonstrate the expression of keratocan by osteoblast lineage cells and its ability to modulate osteoblast function.

This paper sets out to investigate the relative role of Voice Onset Time (VOT) and fundamental frequency ill a language with lexical tone. By comparing English and the Chadic language Kera. this study explores the interaction between the production and perception of voicing, and the role played by voicing, in the phonological structure of the language. The major finding is that the role of VOT and F0 in the perception of voicing differs dramatically between English and Kera subjects with English subjects relying mainly oil VOT and Kera subjects mainly on F0. The phonological implications of these results for Kera are that tone is contrastive while voicing, is not, which is the reverse of English. I will propose that Kera has no [voice] feature. and that the variation in VOT plays a role as a supporting cue to tone, although the exact amount of VOT usage in Kera production and perception differs depending oil the amount of contact with French. The dominance of tone suggests that despite claims that Kera exhibits long-distance voice spreading, what spreads is in fact tone rather than voice. (C) 2008 Elsevier B.V. All rights reserved.