An anther-specific cysteine-rich protein of tomato localized to the tapetum and microspores.
The tapetum is a nutritive tissue of the stamen that is essential for normal microspore development. While numerous tapetal-specific genes have been identified, little information is available on the localization and function of the proteins produced by these genes. The tapetally produced protein 5B-CRP is cysteine-rich, has a secretory signal sequence and lacks an endoplasmic reticulum retention sequence. The 5B-CRP mRNA is expressed specifically within the tapetum and accumulates from premeiosis to tetrad release. Antibodies generated against an Escherichia coli fusion protein only recognized 5B-CRP in the reduced state. The 5B-CRP was detected as a 6 kDa protein in extracts of stamens from microspore meiosis through anthesis and was also observed in extracts from dehisced pollen. In situ, 5B-CRP was localized in stamens to the tapetum and the developing microspores, from the tetrad through early free microspore stages. Based on similarity to proteins with known functions, 5B-CRP may inhibit proteasome activity within the stamen locule.
McNeil
Kenneth J
KJ
Department of Horticultural Science, University of Minnesota, 356 Alderman Hall, St. Paul, MN 55108, USA.
Smith
Alan G
AG
D000595:Amino Acid Sequence; D016384:Consensus Sequence; D003545:Cysteine; D035264:Flowers / Q000166:cytology / Q000378:metabolism*; D015870:Gene Expression / Q000502:physiology; D018551:Solanum lycopersicum / Q000166:cytology / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D010940:Plant Proteins; D003545:Cysteine