Genomic organization of the S locus: Identification and characterization of genes in SLG/SRK region of S(9) haplotype of Brassica campestris (syn. rapa).
In Brassica, two self-incompatibility genes, encoding SLG (S locus glycoprotein) and SRK (S-receptor kinase), are located at the S locus and expressed in the stigma. Recent molecular analysis has revealed that the S locus is highly polymorphic and contains several genes, i.e., SLG, SRK, the as-yet-unidentified pollen S gene(s), and other linked genes. In the present study, we searched for expressed sequences in a 76-kb SLG/SRK region of the S(9) haplotype of Brassica campestris (syn. rapa) and identified 10 genes in addition to the four previously identified (SLG(9), SRK(9), SAE1, and SLL2) in this haplotype. This gene density (1 gene/5.4 kb) suggests that the S locus is embedded in a gene-rich region of the genome. The average G + C content in this region is 32.6%. An En/Spm-type transposon-like element was found downstream of SLG(9). Among the genes we identified that had not previously been found to be linked to the S locus were genes encoding a small cysteine-rich protein, a J-domain protein, and an antisilencing protein (ASF1) homologue. The small cysteine-rich protein was similar to a pollen coat protein, named PCP-A1, which had previously been shown to bind SLG.
Suzuki
G
G
Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan. gsuzuki@bios.tohoku.ac.jp
Kai
N
N
Hirose
T
T
Fukui
K
K
Nishio
T
T
Takayama
S
S
Isogai
A
A
Watanabe
M
M
Hinata
K
K
D000595:Amino Acid Sequence; D001482:Base Composition; D001937:Brassica / Q000201:enzymology / Q000235:genetics*; D003001:Cloning, Molecular; D004251:DNA Transposable Elements / Q000235:genetics; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant / Q000235:genetics*; D008040:Genetic Linkage / Q000235:genetics; D018745:Genome, Plant; D006023:Glycoproteins / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D020161:Physical Chromosome Mapping; D010940:Plant Proteins / Q000235:genetics*; D018514:Plant Structures / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D011110:Polymorphism, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D004251:DNA Transposable Elements; D006023:Glycoproteins; D010940:Plant Proteins; D012333:RNA, Messenger; C064156:self-incompatibility locus specific glycoprotein, Brassica