Nucleotide sequence of a cloned rice genomic DNA fragment that encodes a 10 kDa prolamin polypeptide

Genetic analysis of cysteine-poor prolamin polypeptides reduced in the endosperm of the rice esp1 mutant

The esp1 mutant CM21 specifically exhibits reduced levels of cysteine-poor (CysP) prolamin bands with pIs of 6.65, 6.95, 7.10, and 7.35 in rice seed. Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis demonstrated that the bands with pIs 6.65, 6.95, and 7.35 are encoded by different structural genes. These results suggest that the Esp1 locus encodes a regulatory factor involved in the synthesis and/or accumulation of CysP prolamin molecules. Isoelectric focusing (IEF) analysis of CysP prolamins in chromosome substitution lines showed that structural genes for bands with pI values of 6.95, 7.10, and 7.35, which are reduced in esp1 mutant lines, are located as a gene cluster in the 44.2 cM region on chromosome 5.

Amino acid variation in the 10 kDa Oryza prolamin seed storage protein

The deduced amino acid variability for the 10 kDa prolamin was determined for 16 Oryza species, both cultivated (rice) and wild. Prolamin, a seed storage protein and site of nitrogen and sulfur accumulation, is sequestered in the subaleurone layer of the starchy endosperm for use during seedling germination. The 10 kDa prolamin amino acid distribution for the cultivated species (O. sativa and O. glaberrima) was determined and compared to those of wild and, hitherto unknown, noncultivated Oryza species. Four wild species (O. granulata, O. australiensis, O. brachyantha, and O. meyeriana) exhibited the greatest residue heterogeneity in both the signal and mature peptide regions. A breakdown of the essential amino acid variance among three Central/South American and one African endemic wild species is also presented and compared with those of rice.

The 5' flanking region of the rat beta 3-adrenergic receptor gene: divergence with the human gene and implications for species-specific gene expression

beta 3-adrenergic receptor mRNAs exhibit species-specific expression (human vs. rodent) in distinct anatomical regions and appear to be expressed abundantly within rodent adipose tissue, but only at low levels within corresponding human tissues. In order to determine the genetic basis of the differential expression of the rat and human beta 3-adrenergic receptor genes, we cloned and sequence the rat gene and compared the 5' flanking regions of the two genes to identify potential discriminators in transcriptional regulation. We have found that the rat and human beta 3-adrenergic receptor 5' flanking regions are only 67% similar, unlike the close sequence similarity observed between the coding blocks (> 90%) and also observed between species for the 5' flanking regions of other beta-adrenergic receptor subtype genes (> 90%). In addition, the rat beta 3-adrenergic receptor gene lacks the four potential cAMP responsive elements identified within the 5' flanking region of the human receptor gene. The striking divergence in regulatory sequences between the rat and human beta 3-adrenergic receptor genes may potentially explain the differences in species-specific expression and tissue localization of the rat and human receptor mRNAs.

Nucleotide sequence of the maize chloroplast rpo B/C1/C2 operon: comparison between the derived protein primary structures from various organisms with respect to functional domains

The genes (rpo B/C1/C2) coding for the beta, beta', beta" subunits of maize (Zea mays) chloroplast RNA polymerase have been located on the plastome and their nucleotide sequences established. The operon is part of a large inversion with respect to the tobacco and spinach chloroplast genomes and is flanked by the genes trnC and rps2. Notable features of the nucleotide sequence are the loss of an intron in rpoC1 and an insertion of approximately 450 bp in rpoC2 compared to the dicotyledons tobacco, spinach and liverwort. The derived amino acid sequence of this additional monocotyledon specific sequence is characterized by acidic heptameric repeat units containing stretches of glutamic acid, tyrosines and leucines with regular spacing. Other structural motifs, such as a nucleotide binding domain in the beta subunit and a zinc finger in the beta' subunit, are compared at the amino acid level throughout the RNA polymerase subunits with the enzymes from other organisms in order to identify functionally important conserved regions.