Colocalization of CHL1 and ROBO1 During Embryonic Development of Mouse Brain

Abstract

Axons are an integral part of a neuron responsible for transmitting electrical signals within the brain. It is important to understand the mechanics of axon growth, including: how growth cones function and which proteins are involved in axon migration and how they co‐exist with other proteins. This hierarchy of information is essential to combat neurological disorders such as Alzheimer's disease. We currently know of several families of proteins that play major roles in regulating axon guidance. Two such families are neural cell adhesion molecules (CAMs) of the immunoglobulin superfamily (Maness and Schachner, 2007) and the family of SLIT proteins (Andrews, et al., 2007). Close Homolog of L1 (CHL1), a CAM, is part of the mammalian L1 family, which is known to play a role in axon growth and migration of developing neurons (Wright, et al., 2007). Roundabout1 (ROBO1), also a member of the immunoglobulin super family, plays a role in axon guidance in the developing forebrain by serving as a receptor for the guidance cue, SLIT1 (Andrews, et al., 2007). Our objective in this study is to investigate a potential interaction between CHL1 and ROBO1. We hypothesize that these two proteins function together to regulate SLIT‐mediated axon growth in developing neurons. The first step in our investigation involved the use of co‐immunofluorescence staining to visualize CHL1 and ROBO1 colocalization. We demonstrate here that CHL1 and ROBO1 do colocalize in the intermediate zone of the cerebral cortex during axonal outgrowth (E15) and axonal targeting (E16). This colocalization suggests an interaction between these two proteins that may help promote axon growth and guidance. This work was supported by Marymount University's DISCOVER Program and the Clare Boothe Luce Foundation.