Development Genes and Evolution

, Volume 216, Issue 4, pp 185–197

Molecular characterization and embryonic expression of innexins in the leech Hirudo medicinalis

Original Article

Abstract

Gap junctions are direct intercellular channels that permit the passage of ions and small signaling molecules. The temporal and spatial regulation of gap junctional communication is, thus, one mechanism by which cell interactions, and hence cell properties and cell fate, may be regulated during development. The nervous system of the leech, Hirudo medicinalis, is a particularly advantageous system in which to study developmental mechanisms involving gap junctions because interactions between identified cells may be studied in vivo in both the embryo and the adult. As in most invertebrates, gap junctions in the leech are composed of innexin proteins, which are distantly related to the vertebrate pannexins and are encoded by a multi-gene family. We have cloned ten novel leech innexins and describe the expression of these, plus two other previously reported members of this gene family, in the leech embryo between embryonic days 6 and 12, a period during which the main features of the central nervous system are established. Four innexins are expressed in neurons and two in glia, while several innexins are expressed in the excretory, circulatory, and reproductive organs. Of particular interest is Hm-inx6, whose expression appears to be restricted to the characterized S cell and two other neurons putatively identified as presynaptic to this cell. Two other innexins also show highly restricted expressions in neurons and may be developmentally regulated.

Keywords

Gap junction Innexin Pannexin Leech Hirudo medicinalis Embryonic gene expression 

Supplementary material

427_2005_48_Fig10_ESM.gif (247 kb)

Multiple sequence alignment to show the translated protein sequence of the leech Innexin genes discussed in the text. Identical residues are shaded. Note that Hm-inx7, Hm-inx8 and Hm-inx10 are partial sequences and only the C-terminal portion of the sequence is known. Accession numbers of the corresponding cDNA sequences are as follows: Hm-inx1 = AJ512833; Hm-inx2 = AJ512834; Hm-inx3 = DQ228700; Hm-inx4 = DQ228701; Hm-inx5 = DQ228702; Hm-inx6 = DQ228703; Hm-inx7 = DQ228704; Hm-inx8 = DQ228705; Hm-inx9 = DQ228706; Hm-inx10 = DQ228707; Hm-inx11 = DQ228708; Hm-inx12 = DQ228709

427_2005_48_Fig11_ESM.gif (306 kb)

Multiple sequence alignment to show the translated protein sequence of the leech Innexin genes discussed in the text. Identical residues are shaded. Note that Hm-inx7, Hm-inx8 and Hm-inx10 are partial sequences and only the C-terminal portion of the sequence is known. Accession numbers of the corresponding cDNA sequences are as follows: Hm-inx1 = AJ512833; Hm-inx2 = AJ512834; Hm-inx3 = DQ228700; Hm-inx4 = DQ228701; Hm-inx5 = DQ228702; Hm-inx6 = DQ228703; Hm-inx7 = DQ228704; Hm-inx8 = DQ228705; Hm-inx9 = DQ228706; Hm-inx10 = DQ228707; Hm-inx11 = DQ228708; Hm-inx12 = DQ228709

427_2005_48_Fig12_ESM.gif (273 kb)

Multiple sequence alignment to show the translated protein sequence of the leech Innexin genes discussed in the text. Identical residues are shaded. Note that Hm-inx7, Hm-inx8 and Hm-inx10 are partial sequences and only the C-terminal portion of the sequence is known. Accession numbers of the corresponding cDNA sequences are as follows: Hm-inx1 = AJ512833; Hm-inx2 = AJ512834; Hm-inx3 = DQ228700; Hm-inx4 = DQ228701; Hm-inx5 = DQ228702; Hm-inx6 = DQ228703; Hm-inx7 = DQ228704; Hm-inx8 = DQ228705; Hm-inx9 = DQ228706; Hm-inx10 = DQ228707; Hm-inx11 = DQ228708; Hm-inx12 = DQ228709

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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Section of Cell and Developmental Biology, Division of Biological Sciences, NSB 6213University of California, San DiegoLa JollaUSA
  2. 2.Department of PsychiatryUniversity of California San Diego and the VA San Diego Healthcare SystemLa JollaUSA

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