Journal of Muscle Research & Cell Motility

, Volume 24, Issue 7, pp 431–438

The entire cDNA sequences of projectin isoforms of crayfish claw closer and flexor muscles and their localization

  • Taichi Oshino
  • Jinen Shimamura
  • Atsushi Fukuzawa
  • Koscak Maruyama
  • Sumiko Kimura
Article

DOI: 10.1023/A:1027313204786

Cite this article as:
Oshino, T., Shimamura, J., Fukuzawa, A. et al. J Muscle Res Cell Motil (2003) 24: 431. doi:10.1023/A:1027313204786

Abstract

Projectin is a giant protein related to twitchin and titin/connectin, that is found in arthropod striated muscle. The complete sequence of a 1 MDa projectin from Drosophila muscle was recently deduced from a thorough analysis of the genomic DNA (Southgate and Ayme-Southgate, 2001). Here we report the complete sequence for projectin from crayfish claw closer muscle (8625 residues; 962,634 Da). The N-terminal sequence contains 12 unique 19-residue repeats rich in glutamic acid (E) and lysine (K). This region, termed the EK region, is clearly distinguishable from the PEVK-like domain of Drosophila projectin. The sequence of crayfish flexor projectin differs from that of closer muscle projectin in that there is a 114-residue deletion and a 35-residue insertion in the N-terminal region. Immunofluorescence microscopy demonstrated that projectin is mainly localized within the sarcomeric A band in both closer and flexor muscles, although the N-terminal region was shown to extrude into the I band region. In the closer muscles, invertebrate connectin (D-titin) connects the Z line to the edge of the A band (Fukuzawa et al., 2001). We have shown that invertebrate connectin is also present in flexor muscle sarcomeres, although in very low abundance.

Copyright information

© Kluwer Academic Publishers 2003

Authors and Affiliations

  • Taichi Oshino
    • 1
  • Jinen Shimamura
    • 1
  • Atsushi Fukuzawa
    • 1
  • Koscak Maruyama
    • 1
    • 2
  • Sumiko Kimura
    • 1
    • 2
  1. 1.Department of Biology, Faculty of ScienceChiba UniversityChibaJapan
  2. 2.National Center for University Entrance ExaminationsTokyoJapan