Variations in glutamine deamidation for a Châtelperronian bone assemblage as measured by peptide mass fingerprinting of collagen

Peptide mass fingerprinting of bone collagen (ZooMS) has previously been proposed as a method to calculate the extent of the non-enzymatic degradation of glutamine into glutamic acid (deamidation). Temporal and spatial variation of glutamine deamidation at a single site, however, has not been investigated. Here we apply ZooMS screening of Châtelperronian and Early Holocene bone specimens from Quinçay, France, to explore temporal and spatial variation in glutamine deamidation. Our results indicate that chronological resolution is low, while spatial variation is high. Nevertheless, our analysis allows the identification of bone specimens that have undergone diagenetic histories remarkably different (either in length or in type) from spatially related bone specimens. Therefore, ZooMS ammonium-bicarbonate screening is capable of testing bone assemblage homogeneity, which could guide subsequent analysis and interpretation.Human Origin

Spatial, temporal and subcellular localization of islet-brain 1 (IB1), a homologue of JIP-1, in mouse brain.

Islet-brain 1 (IB1) was recently identified as a DNA-binding protein of the GLUT2 gene promoter. The mouse IB1 is the rat and human homologue of the Jun-interacting protein 1 (JIP-1) which has been recognized as a key player in the regulation of c-Jun amino-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways. JIP-1 is involved in the control of apoptosis and may play a role in brain development and aging. Here, IB1 was studied in adult and developing mouse brain tissue by in situ hybridization, Northern and Western blot analysis at cellular and subcellular levels, as well as by immunocytochemistry in brain sections and cell cultures. IB1 expression was localized in the synaptic regions of the olfactory bulb, retina, cerebral and cerebellar cortex and hippocampus in the adult mouse brain. IB1 was also detected in a restricted number of axons, as in the mossy fibres from dentate gyrus in the hippocampus, and was found in soma, dendrites and axons of cerebellar Purkinje cells. After birth, IB1 expression peaks at postnatal day 15. IB1 was located in axonal and dendritic growth cones in primary telencephalon cells. By biochemical and subcellular fractionation of neuronal cells, IB1 was detected both in the cytosolic and membrane fractions. Taken together with previous data, the restricted neuronal expression of IB1 in developing and adult brain and its prominent localization in synapses suggest that the protein may be critical for cell signalling in developing and mature nerve terminals