ISSN:
1617-4623
Schlagwort(e):
Maize
;
Zein
;
Gene cluster
;
Repetitive sequence
;
Cos mapping
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Summary The genes encoding the α-zein proteins of maize constitute a large multigene family of some 75 genes. This multigene family can be divided into four subfamilies based on the nucleotide sequences of their genes and the deduced amino acid sequences of their proteins. We describe for the first time evidence of a clustering of five α-zein subfamily 4 (SF4) genes that are members of one of the major α-zein subfamilies in a 56 kb region of the genome of the maize inbred line W22. None of the other three known α-zein gene subfamilies (SF1, SF2, or SF3) are present in this cluster. The genomic region was reconstructed using restriction endonuclease maps to identify and align three overlapping cosmid clones isolated from a genomic library. The α-zein genes are not evenly spaced; the minimum distance between genes is 3.5 kb; the maximum is 13 kb. All the α-zein genes in the cluster have the same transcriptional orientation. The location and sequences of some of the repetitive DNA elements in this gene cluster were determined. We estimate that there are a minimum of eight repetitive DNA elements in this region. The sequences of the repetitive elements (not functionally defined) are located between or among the α-zein genes. The regions containing two of these repetitive elements (Rep1 and Rep4) have been sequenced; they are about 15 kb apart in the genome. These repetitive elements have similar sequences for about 300 by out of the 400 by compared. The regions of sequence similarity, however, are in reverse orientation to one another. Both repetitive elements contain replication origin-like sequences. In addition, Rep4 contains two repeats of a five-base sequence that appear to define its presumptive ends. The presence of the short direct repeats flanking the Rep4 element suggests that the Rep4 element might have originated from a transposition event.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00279804
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