Identification of aldolase C compartments in the mouse cerebellar cortex by olivocerebellar labeling

Abstract

Aldolase C (zebrin II) is expressed in Purkinje cells aligned in complicated longitudinal stripe-shaped compartments. The tight link between these aldolase C compartments and the topographic olivocerebellar projection to them has made it possible to identify each compartment as a target of a specific subarea of the inferior olive and thus as a functionally distinct entity in the rat. However, it is unknown whether the overall organization of aldolase C compartments is preserved in other mammals. In this study, we tried to clarify this organization in the mouse, which is more useful in genetic studies than the rat, by identifying each aldolase C compartment in terms of the olivocerebellar projection pattern. First, aldolase C compartments were reconstructed from serial sections throughout the cerebellar cortex. Aldolase C and olivocerebellar climbing fibers were then doubly labeled by small injections of biotinylated dextran amine into various areas of the inferior olive. Climbing fibers were topographically distributed on a specific linked pair of aldolase C compartments in the rostral and caudal cerebellum. The overall relationship between aldolase C compartments and the topographic olivocerebellar projection to them in the mouse was similar to that in the rat, except for some minor differences, suggesting that the aldolase C compartments and olivocerebellar projection are organized according to a common fundamental organization in the mouse and rat. This allowed the unequivocal identification of all aldolase C compartments in the mouse by referring to the definition and nomenclature in the rat.

Structure–Function Relationships between Aldolase C/Zebrin II Expression and Complex Spike Synchrony in the Cerebellum

“…1B). The characteristic width and sequence of mouse aldolase C compartments in Crus II (Sugihara and Quy, 2007) aided the identification and naming of each compartment. The entire location of all the compartments in the imaging field was manually mapped in advance because we later injected a red fluorescent dye, Alexa 594, which would blur the boundaries.…”

“…We chose Crus IIa because it is easy to access and has unique and consistent aldolase C banding with relatively wide compartments (4ϩ to 7ϩ; Sugihara and Quy, 2007), which facilitates the analysis of synchrony between PC populations. Spontaneous dendritic calcium transients of PCs, which reflect complex spikes (Kitamura and Häusser, 2011; Fig.…”

“…PCs heterogeneously express a variety of proteins and biological molecules to form longitudinal stripes within the cerebellum (Brochu et al, 1990;Oberdick et al, 1998;Hashimoto and Mikoshiba, 2003;Sarna et al, 2006;Sugihara and Quy, 2007). Among these molecules, aldolase C/zebrin II is most commonly used as a marker for these stripes.…”

“…A multi-electrode study has shown some correlation between complex spike synchrony and aldolase C compartments to a resolution of several hundred micrometers . However, the width of an aldolase C compartment can be up to 300 -400 m in mice (Sugihara and Quy, 2007), and that of microzones may be as low as 100 m (Ozden et al, 2009). Studies with high spatial resolution are therefore essential to clarify the precise relationship between microzones and aldolase C compartments.…”

Early development of the nervous system of the eutherian <i>Tupaia belangeri</i>

“…Other groups have subsequently studied zebrin-IIimmunoreactive cerebellar compartments in order to carry out the following investigations: (1) interspecific comparison with the tammar wallaby (Macropus eugenii) (Marzban et al 2012), microchiropteran bats (Kim et al, 2009), hummingbirds (Aves: Trochilidae) (Iwaniuk et al, 2009), chicks (Gallus domesticus) (Marzban et al, 2010), pigeons (Columba livia) (Pakan et al, 2007; for an overview, see Marzban and Hawkes, 2011); (2) visualization of aldolase C with fluorescence through gene manipulation with the help of aldolase CVenus knock-in mice to facilitate studies on cerebellar compartmentalization (Fujita et al, 2014); (3) presentation of parasagittal stripes in the vermis which, complementary to zebrin II, are immunoreactive for neurofilament H (Demilly et al, 2011); (4) identification of links between the olivocerebellar projection and zebrin-immunoreactive compartments in the laboratory mouse (Sugihara and Quy, 2007) and in marmoset (Callithrix jacchus) (Fujita et al, 2010); (5) clarification of the role played by the helix-loop-helix (HLH) transcription factor early B-cell factor 2 (EBF2) (Croci et al, 2006); and (6) evaluation of the cerebellar connectivity in spinocerebellar ataxia type 1 (Solodkin et al, 2011). The second main research area of Wolfgang Knabe and colleagues, whose roots date back to the former anatomical department of Hans-Jürg Kuhn, continued previous projects on the retina, then served as a bridge between the retina and the forebrain, and, thereafter, was successively expanded to include the entire brain, spinal cord, neural crest, and the placodes.…”