Plant Genome II Conference
Town & Country Conference Center, San Diego, CA, January, 1994.
PG-II: IDENTIFICATION OF A CALRETICULIN HOMOLOGOUS GENE IN PLANTS:
DEVELOPMENTAL REGULATION AND AMINO ACID SEQUENCE DEDUCED FROM
cDNA
IDENTIFICATION OF A CALRETICULIN HOMOLOGOUS GENE IN PLANTS:
DEVELOPMENTAL REGULATION AND AMINO ACID SEQUENCE DEDUCED FROM
cDNA.
F.Q. Chen, P.M. Hayes, D. Mulrooney, and A. Pan, Dept. of Crop
and Soil Science, Oregon State University, Corvallis, OR
97331-3002.
A 1450 bp cDNA clone more than 60% homologous to the
nucleotide sequences of animal calreticulin, a calcium binding
protein with both high affinity low capacity and low affinity
high capacity binding sites, was identified from a 3 day old
fertilized ovary cDNA library of barley (Hordeum vulgare L.)
through differential screening. The expression of the gene was
considerably elevated after fertilization, but the elevation was
attenuated by the selective chromosome elimination in the
interspecific hybridization of Hordeum vulgare x Hordeum
bulbosum. The cDNA clone has an open reading frame that encodes
an acidic protein of 368 residues with a mol. wt. of 41,931
daltons. The deduced amino acid sequence shares more than 50% of
homology with animal calreticulin and has a considerable amount
of conservative residue substitution. Like animal calreticulin,
the deduced amino acid sequence displays the three zone
characteristic: the nearly neutral N terminal region, the praline
rich central region with internal repeats of AKKPEDWDD, and the
polyacidic C terminal region. However, compared to animal
calreticulin, the aspartic acid residue is more predominant than
the glutamic acid residue in the polyacidic C terminal region,
and the ER retention signal sequence is HDEL instead of KDEL.
The results support the ubiquitous nature of calreticulin and
also reveal the marked difference in the deduced animo acid
sequences between animal and plant.
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