Skip to main content
PMC home page
The Journal of Cell Biology logoLink to The Journal of Cell Biology
. 1975 Mar 1;64(3):705–710. doi: 10.1083/jcb.64.3.705

The occurrence of actinlike filaments in association with migrating pigment granules in frog retinal pigment epithelium

RL Murray, MW Dubin
PMCID: PMC2109551  PMID: 1080152

Abstract

In the retina of the frog and certain other animals, melanin pigment granules move in response to light so as to shield photoreceptor outer segments. The granules are contained within the cells of the pigment epithelium (PE) which lie as a continuous sheet between the neural retina and the choroid. Moderate illumination of the eye causes the melanin granules to move from a region within a PE cell body into numerous fingerlike extensions of the cell which interdigitate with the receptor outer segments. This migration takes many minutes and is reversed when the light falling on the eye increases in intensity. Several reviews are concerned with the early descriptions of this phenomenon (6,30) and with more recent experiments (1,5,19). The mechanism of the pigment granule motion is undetermined although there are studies concerning PE ultrastructure (8, 23, 31), scanning electron microscopy of the fingerlike extensions of the PE cells (27), the role of the PE in photoreceptor phagocytosis (32), the nature of the pigment granules (19), and the action spectrum of the light which induces the migration (16). This study reports the presence of a system of microfilaments associated with the pigment granules in the fingerlike extensions processes of the PE cells. We demonstrate by heavy meromyosin (HMM) labeling that the filaments are actinlike in character and suggest that these filaments could be responsible for the migration of the melanin pigment granules.

Full Text

The Full Text of this article is available as a PDF (1.2 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Ali M. A. Les réponses rétinomotrices: caractères et mécanismes. Vision Res. 1971 Nov;11(11):1225–1288. doi: 10.1016/0042-6989(71)90010-1. [DOI] [PubMed] [Google Scholar]
  2. Brown K. T. An early potential evoked by light from the pigment epithelium-choroid complex of the eye of the toad. Nature. 1965 Sep 18;207(5003):1249–1253. doi: 10.1038/2071249a0. [DOI] [PubMed] [Google Scholar]
  3. Dowling J. E. Synaptic organization of the frog retina: an electron microscopic analysis comparing the retinas of frogs and primates. Proc R Soc Lond B Biol Sci. 1968 Jun 11;170(1019):205–228. doi: 10.1098/rspb.1968.0034. [DOI] [PubMed] [Google Scholar]
  4. Hudspeth A. J., Yee A. G. The intercellular junctional complexes of retinal pigment epithelia. Invest Ophthalmol. 1973 May;12(5):354–365. [PubMed] [Google Scholar]
  5. Ishikawa H., Bischoff R., Holtzer H. Formation of arrowhead complexes with heavy meromyosin in a variety of cell types. J Cell Biol. 1969 Nov;43(2):312–328. [PMC free article] [PubMed] [Google Scholar]
  6. Ishikawa H., Bischoff R., Holtzer H. Mitosis and intermediate-sized filaments in developing skeletal muscle. J Cell Biol. 1968 Sep;38(3):538–555. doi: 10.1083/jcb.38.3.538. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. KLUG A., BERGER J. E. AN OPTICAL METHOD FOR THE ANALYSIS OF PERIODICITIES IN ELECTRON MICROGRAPHS, AND SOME OBSERVATIONS ON THE MECHANISM OF NEGATIVE STAINING. J Mol Biol. 1964 Dec;10:565–569. doi: 10.1016/s0022-2836(64)80081-4. [DOI] [PubMed] [Google Scholar]
  8. Liebman P. A., Carroll S., Laties A. Spectral sensitivity of retinal screening pigment migration in the frog. Vision Res. 1969 Mar;9(3):377–384. doi: 10.1016/0042-6989(69)90084-4. [DOI] [PubMed] [Google Scholar]
  9. Miller W. H., Cawthon D. F. Pigment granule movement in Limulus photoreceptors. Invest Ophthalmol. 1974 May;13(5):401–405. [PubMed] [Google Scholar]
  10. Murphy D. B., Tilney L. G. The role of microtubules in the movement of pigment granules in teleost melanophores. J Cell Biol. 1974 Jun;61(3):757–779. doi: 10.1083/jcb.61.3.757. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Nachmias V. T., Huxley H. E. Electron microscope observations on actomyosin and actin preparations from Physarum polycephalum, and on their interaction with heavy meromyosin subfragment I from muscle myosin. J Mol Biol. 1970 May 28;50(1):83–90. doi: 10.1016/0022-2836(70)90105-1. [DOI] [PubMed] [Google Scholar]
  12. PORTER K. R., YAMADA E. Studies on the endoplasmic reticulum. V. Its form and differentiation in pigment epithelial cells of the frog retina. J Biophys Biochem Cytol. 1960 Sep;8:181–205. doi: 10.1083/jcb.8.1.181. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Pollard T. D., Weihing R. R. Actin and myosin and cell movement. CRC Crit Rev Biochem. 1974 Jan;2(1):1–65. doi: 10.3109/10409237409105443. [DOI] [PubMed] [Google Scholar]
  14. SABATINI D. D., BENSCH K., BARRNETT R. J. Cytochemistry and electron microscopy. The preservation of cellular ultrastructure and enzymatic activity by aldehyde fixation. J Cell Biol. 1963 Apr;17:19–58. doi: 10.1083/jcb.17.1.19. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Steinberg R. H. Scanning electron microscopy of the bullfrog's retina and pigment epithelium. Z Zellforsch Mikrosk Anat. 1973 Oct 26;143(4):451–463. doi: 10.1007/BF00306765. [DOI] [PubMed] [Google Scholar]
  16. Tilney L. G., Porter K. R. Studies on the microtubules in heliozoa. II. The effect of low temperature on these structures in the formation and maintenance of the axopodia. J Cell Biol. 1967 Jul;34(1):327–343. doi: 10.1083/jcb.34.1.327. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. VENABLE J. H., COGGESHALL R. A SIMPLIFIED LEAD CITRATE STAIN FOR USE IN ELECTRON MICROSCOPY. J Cell Biol. 1965 May;25:407–408. doi: 10.1083/jcb.25.2.407. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Young R. W., Bok D. Participation of the retinal pigment epithelium in the rod outer segment renewal process. J Cell Biol. 1969 Aug;42(2):392–403. doi: 10.1083/jcb.42.2.392. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of Cell Biology are provided here courtesy of The Rockefeller University Press

RESOURCES