Distribution and partial characterization of CREB-like immunoreactivity in the medicinal leech Hirudo
J R Groome1, D Pryma, R M Donahue
1Biology Department, Harvey Mudd College, 1250 North Dartmouth Avenue, Claremont, CA 91711 USA. groome@thuban.ac.hmc.edu
Insights
Researchers identified a cyclic AMP response element binding protein (CREB)-like protein in the medicinal leech Hirudo. This CREB-like protein is present in the central nervous system and various peripheral tissues, suggesting conserved roles in invertebrates.
Area of Science:
- Neuroscience
- Molecular Biology
- Invertebrate Zoology
Background:
- The cyclic AMP response element binding protein (CREB) is a transcription factor crucial for neuronal plasticity and memory in vertebrates.
- Its presence and function in invertebrates, particularly in annelids like the medicinal leech (Hirudo), are less understood.
Purpose of the Study:
- To investigate the presence, distribution, and molecular characteristics of CREB-like proteins in the central nervous system (CNS) and peripheral tissues of the medicinal leech.
- To explore potential neuronal localization and segmental specificity of CREB-like immunoreactivity.
Main Methods:
- Western blotting was employed to detect CREB-immunoreactive proteins in tissue extracts.
- Immunohistochemistry on whole-mount leech ganglia was used to visualize the distribution of CREB-immunoreactive neurons.
- Preabsorption controls were performed to validate antibody specificity.
Main Results:
- A CREB-like protein of approximately 43-44 kDa, similar to mammalian CREB, was identified in leech CNS and peripheral tissues.
- CREB-like immunoreactivity was detected in nuclear extracts of the ventral nerve cord.
- Specific CREB-immunoreactive neurons were localized throughout the leech CNS, with some exhibiting segmental specificity. A separate population of neurons stained for CREM.
Conclusions:
- A CREB-like protein exists in the medicinal leech, with a molecular weight comparable to its mammalian counterpart.
- The distribution of this protein in the CNS and peripheral tissues suggests conserved biological functions.
- The identification of CREB-like neurons provides a basis for further research into its role in leech neurobiology and behavior.
Abstract:
The presence and distribution of immunoreactivity to the cyclic AMP response element binding protein (CREB) were determined in the central nervous system (CNS) and in peripheral tissues of the medicinal leech Hirudo. Western blots revealed several CREB-immunoreactive (CREB-IR) bands including one whose molecular weight (43-44 kDa) was similar to mammalian CREB. The 43-44 kDa CREB-like protein was detected in nuclear extracts of the ventral nerve cord and was not observed following preincubation of the primary antiserum with the epitope sequence. CREB-like immunoreactivity was detected in extracts from each of six regions of the leech CNS, and in extracts from leech body wall musculature, crop, intestine, jaw musculature, pharynx, and salivary tissues. Whole mounts of leech ganglia revealed specific CREB-IR in a restricted population of neurons distributed throughout the leech CNS. Apparent homologues to a pair of CREB-IR dorsolateral neurons were observed in most ganglia along the ventral nerve cord. Several CREB-IR neurons exhibited segmental specificity. A number of neurons stained with an antiserum to the cyclic AMP response element modulator (CREM). These neurons showed no overlap in location with CREB-IR neurons, and this staining was not eliminated with a preabsorption control. Possible roles for a CREB-like protein in the leech are discussed.
