Poly(ADP-ribose) polymerase-1 (Parp-1)-deficient mice demonstrate abnormal antibody responses.

Poly(ADP-ribosylation) of acceptor proteins is an epigenetic modification involved in DNA strand break repair, recombination and transcription. Here we provide evidence for the involvement of poly(ADP-ribose) polymerase-1 (Parp-1) in antibody responses. Parp-1(-/-) mice had increased numbers of T cells and normal numbers of total B cells. Marginal zone B cells were mildly reduced in number, and numbers of follicular B cells were preserved. There were abnormal levels of basal immunoglobulins, with reduced levels of immunoglobulin G2a (IgG2a) and increased levels of IgA and IgG2b. Analysis of specific antibody responses showed that T cell-independent responses were normal but T cell-dependent responses were markedly reduced. Germinal centres were normal in size and number. In vitro purified B cells from Parp-1(-/-) mice proliferated normally and showed normal IgM secretion, decreased switching to IgG2a but increased IgA secretion. Collectively our results demonstrate that Parp-1 has essential roles in normal T cell-dependent antibody responses and the regulation of isotype expression. We speculate that Parp-1 forms a component of the protein complex involved in resolving the DNA double-strand breaks that occur during class switch recombination.

Nocodazole, a microtubule de-polymerising agent, induces apoptosis of chronic lymphocytic leukaemia cells associated with changes in Bcl-2 phosphorylation and expression.

Microtubule active drugs are used in the treatment of malignancies and their mechanism of action in cycling cells is to produce mitotic arrest followed by apoptosis. In this study, we investigate in detail the specificity and mechanism by which a microtubule de-polymerising agent, nocodazole, induces apoptosis in non-cyclingm, i.e. G(0)/G(1), chronic lymphocytic leukaemia (CLL) B-cells. The majority of cases of CLL are sensitive (IC(50)

Alteration of the embryo transcriptome of hexaploid winter wheat (Triticum aestivum cv. Mercia) during maturation and germination.

Grain dormancy and germination are areas of biology that are of considerable interest to the cereal community. We have used a 9,155-feature wheat unigene cDNA microarray resource to investigate changes in the wheat embryo transcriptome during late grain development and maturation and during the first 48 h of postimbibition germination. In the embryo 392 mRNAs accumulated by twofold or greater over the time course from 21 days postanthesis (dpa) to 40 dpa and on through 1 and 2 days postgermination. These included mRNAs encoding proteins involved in amino acid biosynthesis and metabolism, cell division and subsequent cell development, signal transduction, lipid metabolism, energy production, protein turnover, respiration, initiation of transcription, initiation of translation and ribosomal composition. A number of mRNAs encoding proteins of unknown function also accumulated over the time course. Conversely 163 sequences showed decreases of twofold or greater over the time course. A small number of mRNAs also showed rapid accumulation specifically during the first 48 h of germination. We also examined alterations in the accumulation of transcripts encoding proteins involved in abscisic acid signalling. Thus, we describe changes in the level of transcripts encoding wheat Viviparous 1 (Vp1) and other interacting proteins. Interestingly, the transcript encoding wheat Viviparous-interacting protein 1 showed a pattern of accumulation that correlates inversely with germination. Our data suggests that the majority of the transcripts required for germination accumulate in the embryo prior to germination and we discuss the implications of these findings with regard to manipulation of germination in wheat.

A transcriptomics resource for wheat functional genomics.

Grain development, germination and plant development under abiotic stresses are areas of biology that are of considerable interest to the cereal community. Within the Investigating Gene Function programme we have produced the resources required to investigate alterations in the transcriptome of hexaploid wheat during these developmental processes. We have single pass sequenced the cDNAs of between 700 and 1300 randomly picked clones from each of 35 cDNA libraries representing highly specific stages of grain and plant development. Annotated sequencing results have been stored in a publicly accessible, online database at http://www.cerealsdb.uk.net. Each of the tissue stages used has also been photographed in detail, resulting in a collection of high-quality micrograph images detailing wheat grain development. These images have been collated and annotated in order to produce a web site focused on wheat development (http://www.wheatbp.net/). We have also produced high-density microarrays of a publicly available wheat unigene set based on the 35 cDNA libraries and have completed a number of microarray experiments which validate their quality.