Molecular cloning and characterization of phytoene desaturase cDNA and leucine-rich repeat protein kinase cDNA from maize.
Item
-
Title
-
Molecular cloning and characterization of phytoene desaturase cDNA and leucine-rich repeat protein kinase cDNA from maize.
-
Identifier
-
AAI9820555
-
identifier
-
9820555
-
Creator
-
Li, Zhaohui.
-
Contributor
-
Adviser: Eleanore T. Wurtzel
-
Date
-
1998
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Biology, Molecular | Biology, Genetics | Biology, Plant Physiology
-
Abstract
-
In plants, carotenoids are major components of the photosynthetic systems as energy trapping pigments, as protectors against photooxidation and as precursors to abscisic acid. For humans, they are the major source for vitamin A and retinoid synthesis. To study regulation of the carotenoid biosynthetic pathway in maize, cDNAs encoding phytoene desaturase (PDS) were cloned and characterized. The protein expressed by one of the Pds cDNA clones catalyzed the desaturation of phytoene to zeta-carotene in Escherichia coli. The Pds cDNA mapped to the viviparous5 locus, whose recessive alleles confer phytoene accumulation in leaf and endosperm of maize. Accumulation of Pds and of Psy (encoding phytoene synthase, PSY0 transcripts in maize endosperm were compared using RT-PCR (reverse transcriptase-polymease chain reaction). While Psy transcript accumulation was temporally regulated in the developing endosperm, Pds transcripts were constant. Results of transcript analysis in maize lines that vary in endosperm carotenoid content suggest that Psy transcript level may be the regulating point for carotenoid biosynthesis in this tissue.;In the course of analyzing Pds cDNA clones, a chimeric clone was found containing part of Pds cDNA and part of a novel receptor-like protein kinase cDNA. Using the partial cDNA sequence of this novel kinase with the combination of RACE (rapid amplification of cDNA ends) and RT-PCR techniques, a small gene family that encodes three different, but sequence-related, receptor-like protein kinases was cloned and characterized. The predicted amino acid sequence showed an extracellular leucine-rich repeat (LRR) domain, a transmembrane domain and an intracellular protein kinase domain and therefore, it was designated as a leucine-rich repeat transmembrane protein kinase (LTK). One of the genes, Ltk1, was mapped near vp5, and was found closely linked to Pds. While the expression of Ltk1 was not tissue-specific, the expression of Ltk2 and Ltk3 was restricted to the endosperm. During the development of maize endosperm, Ltk1 and Ltk2 were temporally expressed at the RNA level, implying possible roles of LTK proteins in endosperm and seed development.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
