Neuroanatomical studies of period gene expression in the hawkmoth, Manduca sexta

Abstract

In the nervous system of the hawkmoth, Manduca sexta, cells expressing the period (per)gene were mapped by in situ hybridization and immunocytochemical methods. Digoxigenin-labeled riboprobes were transcribed from a 1-kb M. sexta per cDNA. Monoclonal anti-PER antibodies were raised to peptide antigens translated from both M. sexta and Drosophila melanogaster per cDNAs. These reagents revealed a widespread distribution of per gene products in M. sexta eyes, optic lobes, brains, and retrocerebral complexes. Labeling for per mRNA was prominent in photoreceptors and in glial cells throughout the brain, and in a cluster of 100-200 neurons adjacent to the accessory medulla of the optic lobes. Daily rhythms of per mRNA levels were detected only in glial cells. PER-like immunoreactivity was observed in nuclei of most neurons and glial cells and in many photoreceptor nuclei. Four neurosecretory cells in the pars lateralis of each brain hemisphere exhibited both nuclear and cytoplasmic staining with anti-PER antibodies. These cells were positively identified as Ia(1) neurosecretory cells that express corazonin immunoreactivity. Anti-corazonin labeled their projections in the brain and their neurohemal endings in the corpora cardiaca and corpora allata. Four pairs of PER-expressing neurosecretory cells previously described in the silkmoth, Anthereae pernyi, are likely to be homologous to these PER/corazonin-expressing Ia(1) cells of M. sexta. Other findings, such as widespread nuclear localization of M. sexta PER and rhythmic expression in glial cells, are reminiscent of the period gene of D. melanogaster, suggesting that some functions of per may be conserved in this lepidopteran species.

Circadian Rhythm Gene Regulation in the Housefly Musca domestica

“…While it can be argued that in some of these studies perhaps the antigenicity did not reflect PER in these insects, or that PER does indeed enter the nucleus at low undetectable levels to engage the negative feedback loop, it is odd that PER antigenicity, whether cycling in the firebrat (Zavodska et al 2003a) or not in the hawkmoth (Wise et al 2002) or the beetle (Frisch et al 1996), or ''not known'' in a variety of other insects (Zavodska et al 2003b), does not usually appear to be nuclear. In fact, on the basis of our initial results with Musca, we might have been tempted to add the housefly to the list of species with ''noncanonical'' patterns of PER regulation.…”

“…observation that, in several insect orders, PER can be found to be exclusively cytoplasmic in its neuronal expression is inconsistent with its ''dedicated'' role as a circadian transcriptional regulator. One group of ''neuronal'' cells that do show nuclear expression of PER are the photoreceptors of both the giant silkmoth A. pernyii and the hawkmoth Manduca sexta where cycles in PER immunoreactivity have been documented in the former species, but not in the latter Wise et al 2002). However, in the hawkmoth, nuclear staining of PER was consistently observed in four neurons within each hemisphere in the pars lateralis, a neurosecretory region, although no circadian cycling of PER abundance was noted (Wise et al 2002).…”

“…One group of ''neuronal'' cells that do show nuclear expression of PER are the photoreceptors of both the giant silkmoth A. pernyii and the hawkmoth Manduca sexta where cycles in PER immunoreactivity have been documented in the former species, but not in the latter Wise et al 2002). However, in the hawkmoth, nuclear staining of PER was consistently observed in four neurons within each hemisphere in the pars lateralis, a neurosecretory region, although no circadian cycling of PER abundance was noted (Wise et al 2002). In contrast, in A. pernyii, a similar group of four cells exclusively express cytoplasmic PER, which cycles in concert with TIM .…”

Constructing a Feedback Loop with Circadian Clock Molecules from the Silkmoth, Antheraea pernyi

“…The regulation of PER subcellular localization in Drosophila differs dramatically from that of A. pernyi and most other insects (15,16). The tobacco hawkmoth, Manduca sexta, is also atypical in that PER nuclear immunostaining (but not PER rhythmicity) is readily detectable in brain neurons (51). However, regardless of how PER subcellular transport is controlled, a Drosophila-like feedback loop may form the core of the circadian clockwork in insects.…”

Complex steroid–peptide–receptor cascade controls insect ecdysis

“…1; see review Žitňan and Adams, 2005) and corazonin immunoreactivity was detected in brain lateral neurosecretory cells in representatives of most major insect orders, except beetles (Veenstra and Davis, 1993;Cantera et al, 1994;Hansen et al, 2001;Roller et al, 2003). In moths these corazonin lateral cells also express the circadian clock protein period (PER) involved in the regulation of circadian rhythms (Sauman and Reppert, 1996;Wise et al, 2002). Connection between circadian rhythms and ecdysis is indicated by extirpation manipulations, which showed that these cells may be important for photoperiod-dependent induction of diapause occurring after pupal ecdysis (Shiga et al, 2003).…”