Isolation of a type 2 metallothionein-like gene preferentially expressed in the tapetum in Zea mays.
A Zea mays cDNA, MZm3-4, was isolated by differential screening of a cDNA library obtained from meiotic stage anthers against a cDNA of 3-week-old seedlings. Northern blot analysis of RNA from different maize tissues and from male reproductive organs at various developmental stages demonstrated expression of a single transcript in anthers, from the pollen mother cell stage through the uninucleated microspore stage. In situ hybridization to anther sections resulted in a distinct signal only in the tapetum. The MZm3-4 cDNA is 743 nucleotides in length and has an open reading frame encoding a protein of 75 amino acids. Sequence comparisons with various databases revealed that MZm3-4 exhibits high similarities with type 2 plant metallothioneins at both the nucleotide and the amino-acid level. Primer extension analysis indicated that MZm3-4 cDNA is deleted of 13bp at the 5' end. Southern blot analysis showed that the MZm3-4 gene may be present in one or two copies in a Z. mays inbred line genome. This is the first report of the isolation of a type 2 metallothionein-like protein in maize. Moreover, the expression of this type 2 metallothionein-like gene is high in the male reproductive organs engaged in microsporogenesis.
Charbonnel-Campaa
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L
Laboratoire d'Ecologie Moléculaire, IBEAS, Université de Pau et des Pays de l'Adour, 64000, Pau, France.
Lauga
B
B
Combes
D
D
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D018744:DNA, Plant / Q000235:genetics; D018628:Gene Dosage; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D008668:Metallothionein / Q000235:genetics*; D008969:Molecular Sequence Data; D010940:Plant Proteins; D011058:Pollen / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014158:Transcription, Genetic; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development
D018076:DNA, Complementary; D018744:DNA, Plant; C414731:MZm3-4 protein, Zea mays; D010940:Plant Proteins; D012333:RNA, Messenger; D008668:Metallothionein