| pubmed-article:2454916 | pubmed:abstractText | We show that maize storage protein translocation across microsomal membranes is mediated by signal recognition particles (SRPs) similar to those described in animal systems (Dobberstein, B. (1978) Hoppe-Seyler's Z. Physiol. Chem. 252, 955-962; Walter, P., and Blobel, G. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 7112-7116). We have prepared a high salt extract from endosperm cell homogenates, from which a ribosome-free fraction was obtained. This fraction is enriched in an SRP-like factor which apparently corresponds to a ribonucleoprotein particle that sediments at about 12 S. The RNA moiety of this 12 S particle is complex, showing a three-band electrophoretic pattern and sedimenting at about 8 S. The fraction restores translocation competence of salt-washed maize microsomes as tested by using a pre-zein message. In contrast to canine SRPs, the maize SRP-like component does not cause a translation arrest of maize storage proteins (zein) in a wheat germ cell-free system. | lld:pubmed |
