Cell proliferation in the forebrain and midbrain of the sea lamprey

Abstract

Cell proliferation in the forebrain and midbrain of the sea lamprey (Petromyzon marinus L.) was investigated by proliferation cell nuclear antigen (PCNA) immunocytochemistry, with BrdU labeling as a complementary technique. Correspondence between proliferation regions and areas of early neuronal differentiation was also assessed using antibodies against HNK-1 early differentiation marker. The brain of late embryos shows a homogeneously thick ventricular zone (VZ) containing PCNA-immunoreactive (PCNA-ir) nuclei. In early prolarvae, several discontinuities formed by PCNA-negative cells, and differences among regions in VZ thickness, become apparent. In late prolarvae and early larvae, these differences in VZ thickness and appearance, as well as the presence of PCNA-negative discontinuities, allowed us to correlate proliferation domains and neuroanatomical regions. In larvae, the number of PCNA-ir cells in the VZs diminish gradually, although a few PCNA-ir cells are present in the ependyma of most regions. In late larvae, proliferation becomes confined to a few ventricular areas (medial pallium, caudal habenula, ventral preoptic recess near the optic nerve, and tuberal portion of the posterior hypothalamic recess). During metamorphosis there appears to be no proliferation, but in upstream adults a few PCNA-ir cells are observed in the most caudal habenula. The characteristics of the proliferative regions revealed in lamprey with PCNA immunocytochemistry show notable differences from those observed in other vertebrates, and these differences may be related to the peculiar life cycle of lampreys.

Identification of aromatase‐positive radial glial cells as progenitor cells in the ventricular layer of the forebrain in zebrafish

“…Cell proliferation was also monitored by using a mouse monoclonal anti-rat PCNA (1:100; clone PC10; Reference MO879, DAKO). This antibody has been shown to react with proliferating cell nuclear antigen (PCNA) in a wide range of species including fish and causes nuclear staining similar to BrdU, as previous studies have shown (Wullimann and Puelles, 1999;Bang et al, 2001;Villar-Cheda et al, 2006). PCNA antibody specificity was tested by the supplier.…”

The lamprey in evolutionary studies

“…In a recent important analysis of neuronal proliferation and differentiation in the brain of embryonic, larval and adult lamprey (Petromyzon marinus), proliferation has been correlated to lamprey brain morphogenesis (Villar-Cheda et al 2006). These authors have shown that differences in the thickness and appearance of the ventricular zone (the portion of the neural tube closest to the ventricle), as well as the presence of proliferation discontinuities, correspond to distinct neuroanatomical regions.…”

Neurochemical characterization of sea lamprey taste buds and afferent gustatory fibers: Presence of serotonin, calretinin, and CGRP immunoreactivity in taste bud bi‐ciliated cells of the earliest vertebrates

“…The immunostaining was developed with 0.6 mg/ml 3-3Ј-diaminobenzidine (DAB; Sigma) and 0.003% H 2 O 2 . PCNA antibody specificity was tested by the supplier, and it was shown that in the lamprey brain it only stains cells in the proliferating ventricular zone (Villar-Cheda et al, 2005, 2006b). Furthermore, no immunostaining was observed in sections processed without the primary antibody.…”

“…Lamprey larvae (n ϭ 3) were placed in 1% BrdU (Sigma) in freshwater for 6 days following previous studies in the larval brain (Villar-Cheda et al, 2006b), in order to label a substantial proportion of cells in these slow-proliferating vertebrates. They were then anesthetized with benzocaine and fixed by immersion in Clarke's fixative (75% ethanol, 25% acetic acid), embedded in paraffin, and cut (10 m thickness) on a rotary microtome.…”

“…Other immunohistochemical markers (tubulin and CR) were used to investigate the taste cells and their innervation. We also investigated the location of proliferating cells in the larval lamprey TBs by means of two methods involving proliferation markers, bromodeoxyuridine (BrdU) labeling and proliferating cell nuclear antigen (PCNA) immunohistochemistry, markers that were previously used in lamprey brain (Tobet et al, 1996;Vidal-Pizarro et al, 2004;Villar-Cheda et al, 2005, 2006b). The present results reveal for the first time the presence of 5-HT, CGRP, and CR in bi-ciliated cells in lamprey TBs and demonstrate the nonproliferative status of the vast majority of cells in the TBs.…”