Biomedical subjects

Martin Skipper

Publications and source records attributed to Martin Skipper.

3 recordsLinked to original sources

PubMed2005

Cloning and transcription analysis of an AGAMOUS- and SEEDSTICK ortholog in the orchid Dendrobium thyrsiflorum (Reichb. f.).

Studies have shown that several plant species possess AGAMOUS (AG) and SEEDSTICK (STK) orthologs. These genes are part of the so-called C- and D MADS-box gene lineages and play key roles in ovule development in Arabidopsis thaliana. We have cloned an AG- and STK ortholog in the orchid Dendrobium thyrsiflorum, named DthyrAG1 and DthyrAG2, respectively, and analyzed their expression patterns. Quantification by real-time RT-PCR analysis shows that both are transcribed in the mature flowers and during ovule development. Localization of the transcripts by in situ hybridization analysis in flowers reveals that both genes are transcribed in the rostellum, stigma, and stylar canal. Expression analysis during ovule development shows that DthyrAG1 is expressed only in the initial periods of placenta- and ovule development, whereas the DthyrAG2 is transcribed throughout ovule development. These results suggest that both C- and D lineage orthologs are involved in various aspects of flower development and that DthyrAG2 have a more prominent role than DthyrAG1 in late ovule development in D. thyrsiflorum.

Arabidopsis↗

PubMed2002

MADS-box gene evolution-structure and transcription patterns.

This study presents a phylogenetic analysis of 198 MADS-box genes based on 420 parsimony-informative characters. The analysis includes only MIKC genes; therefore several genes from gymnosperms and pteridophytes are excluded. The strict consensus tree identifies all major monophyletic groups known from earlier analyses, and all major monophyletic groups are further supported by a common gene structure in exons 1-6 and by conserved C-terminal motifs. Transcription patterns are mapped on the tree to obtain an overview of MIKC gene transcription. Genes that are transcribed only in vegetative organs are located in the basal part of the tree, whereas genes involved in flower development have evolved later. As the universality of the ABC model has recently been questioned, special account is paid to the expression of A-, B-, and C-class genes. Mapping of transcription patterns on the phylogeny shows all three classes of MADS-box genes to be transcribed in the stamens and carpels. Thus the analysis does not support the ABC model as formulated at present.

Amino Acid Sequence↗

PubMed2002

Genes from the APETALA3 and PISTILLATA lineages are expressed in developing vascular bundles of the tuberous rhizome, flowering stem and flower Primordia of Eranthis hyemalis.

In Arabidopsis thaliana expression of the B-class MADS-box genes APETALA3 (AP3) and PISTILLATA (PI) is confined to petals and stamens but in other plant species these genes are also transcribed in non-flower tissues; in Solanum tuberosum they are transcribed specifically in vascular bundles leading to petals and stamens. Transcription analysis of B-class genes in Eranthis hyemalis using reverse transcribed in situ PCR revealed that both AP3 and PI are expressed in developing vascular bundles in the tuberous rhizome, flowering stem and floral primordia. In addition, AP3 and PI transcripts are also found in stems and leaves. These results suggest a more complex role of B-class genes in Eranthis and possible involvement in the development of vascular tissue.

Gene Expression Regulation, Plant↗