Molecular cloning of a carotenoid-associated protein from Cucumis sativus corollas: homologous genes involved in carotenoid sequestration in chromoplasts

Plant J. 1996 Dec;10(6):1111-8. doi: 10.1046/j.1365-313x.1996.10061111.x.

Abstract

Chromoplasts are carotenoid-accumulating plastids found in the corollas and fruits of many higher plants. In most cases, the pigment in these plastids is accumulated with the aid of carotenoid-associated proteins located within unique structures. This paper reports the isolation and characterization of the cDNA (CHRC) from Cucumis sativus corollas which encodes the chromoplast-specific carotenoid-associated protein CHRC. The transit peptide cleavage site was determined and, using a chloroplast uptake system, it is shown that CHRC can be post-translationally targeted to these plastids where it is peripherally associated with thylakoids. Analysis of CHRC transcript level in Cucumis sativus revealed its temporal and tissue-specific regulation: the transcript was detected only in corollas, where its level increased in parallel to flower development, peaking just before anthesis. CHRC shares significant homology (59%) with the gene coding for fibrillin-a protein in Capsicum annuum red fruits whose function is essentially identical to that of CHRC. A CHRC fragment including the potential active site of the protein was used as a probe in Northern blot analyses of floral and fruit tissues from various plants containing chromoplasts of different types: CHRC homologs of similar sizes were revealed in all cases. The existence of a group of homologous genes coding for chromoplast-specific proteins which aid in the sequestration of carotenoids within specific structures is proposed.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Biological Transport
  • Carotenoids / metabolism*
  • Carrier Proteins / genetics*
  • Carrier Proteins / metabolism
  • Cell Compartmentation
  • Cell Nucleus / genetics
  • Cloning, Molecular
  • Cucumis sativus / chemistry
  • Cucumis sativus / genetics*
  • DNA, Complementary / genetics
  • Genes, Plant*
  • Molecular Sequence Data
  • Plant Proteins*
  • Plant Shoots / chemistry
  • Plastids / metabolism*
  • Protein Biosynthesis
  • Protein Processing, Post-Translational
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Transcription, Genetic

Substances

  • CHRC protein, Cucumis sativus
  • Carrier Proteins
  • DNA, Complementary
  • Plant Proteins
  • Carotenoids

Associated data

  • GENBANK/X95593