title: The b-32 protein from maize endosperm: characterization of genomic sequences encoding two alternative central domains.
abstract: As derived from a cDNA clone, the structure of the b-32 protein of Zea mays, a putative regulatory factor of zein expression, has a central acidic region separated by two domains covered by secondary structure motifs. In this work, three b-32 genomic clones were selected from two genomic libraries obtained from the maize inbred lines W64A and A69Y. The nucleotide sequences of the complete coding region of each b-32 gene, as well as long stretches of their 5' and 3' flanking regions, were determined. Introns are not present in the b-32 genomic sequences. Minor variations among the three genes and an earlier reported b-32 cDNA indicates that they constitute a gene family showing a characteristic polymorphism. Such a polymorphism is highly evident in large segments of the upstream regulatory sequences. Interestingly, when compared with cDNA (W64A) or with gene b-32.120 (W64A), the genes b-32.129 (W64A) and b-32.152 (A69Y) show three jumps of the reading frame in the central part of the coding region, resulting in a completely different sequence of the b-32 protein central domain. In all cases, variations in the N- and C-terminal domains account only for microheterogeneity.
authors.affiliation: Istituto Sperimentale per la Cerealicoltura, Sezione di Bergamo, Italy.
authors.forename: H
authors.initials: H
authors.lastname: Hartings
authors.forename: N
authors.initials: N
authors.lastname: Lazzaroni
authors.forename: P A
authors.initials: PA
authors.lastname: Marsan
authors.forename: A
authors.initials: A
authors.lastname: Aragay
authors.forename: R
authors.initials: R
authors.lastname: Thompson
authors.forename: F
authors.initials: F
authors.lastname: Salamini
authors.forename: N
authors.initials: N
authors.lastname: Di Fonzo
authors.forename: J
authors.initials: J
authors.lastname: Palau
authors.forename: M
authors.initials: M
authors.lastname: Motto
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D017343:Genes, Plant; D008969:Molecular Sequence Data; D005810:Multigene Family; D010940:Plant Proteins / Q000235:genetics*; D010944:Plants / Q000235:genetics*; D011110:Polymorphism, Genetic; D003313:Zea mays / Q000235:genetics
chemical_list: C070555:B-32 protein, Zea mays; D010940:Plant Proteins; D004247:DNA