The b-32 protein from maize endosperm: characterization of genomic sequences encoding two alternative central domains
✍ Scribed by Hans Hartings; Nadia Lazzaroni; Paolo Ajmone Marsan; Anna Aragay; Richard Thompson; Francesco Salamini; Natale Fonzo; Jaume Palau; Mario Motto
- Book ID
- 104615322
- Publisher
- Springer
- Year
- 1990
- Tongue
- English
- Weight
- 746 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0167-4412
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✦ Synopsis
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 Nand C-terminal domains account only for microheterogeneity.