ABSTRACT
In the developing central nervous system, cell departure from the apical surface is the initial and fundamental step to form the 3D, organized architecture. Both delamination of differentiating cells and repositioning of progenitors to generate outer radial glial cells (oRGs) contribute to mammalian neocortical expansion; however, a comprehensive understanding of their mechanisms is lacking. Here, we demonstrate that Lzts1, a molecule associated with microtubule components, promotes both cell departure events. In neuronally committed cells, Lzts1 functions in apical delamination by altering apical junctional organization. In apical RGs (aRGs), Lzts1 expression is variable, depending on Hes1 expression levels. According to its differential levels, Lzts1 induces diverse RG behaviors: planar division, oblique divisions of aRGs that generate oRGs, and their mitotic somal translocation. Loss-of-function of lzts1 impairs all these cell departure processes. Thus, Lzts1 functions as a master modulator of cellular dynamics, contributing to increasing complexity of the cerebral architecture during evolution.
Subject(s)
Cerebrum/growth & development , Cerebrum/metabolism , Ependymoglial Cells/metabolism , Neurogenesis , Neurons/metabolism , Tumor Suppressor Proteins/metabolism , Animals , Cell Movement , Cerebrum/cytology , Ependymoglial Cells/cytology , Mice , Mice, Transgenic , Neurons/cytology , Transcription Factor HES-1/genetics , Transcription Factor HES-1/metabolism , Tumor Suppressor Proteins/geneticsABSTRACT
Activities of hexokinase (HK), glucokinase (GK) and pyruvate kinase (PK), were measured. The expression of GK mRNA was investigated using reverse transcription-polymerase chain reaction (RT-PCR) in leukocytes (WBC) of dogs and cats. No significant differences between dogs and cats were found in concentrations of blood glucose and plasma insulin. Dog WBC showed GK activities and the specific fragment with predicted size of 574 bp containing conserved region including glucose- and ATP-binding domains of GK as determined with RT-PCR. However, in cat WBC, the activities and specific fragment of GK were absent. After fasting, the activities and gene expression of GK decreased greatly in the dog WBC. The cat WBC had significantly higher activities of HK and PK than dog WBC.
