Sexual reproduction in higher plants I: fertilization and the initiation of zygotic program.

Sexual plant reproduction is a critical developmental step in the life cycle of higher plants, to allow maternal and paternal genes to be transmitted in a highly regulated manner to the next generation. During evolution, a whole set of signal transduction machinery is developed by plants to ensure an error-free recognition between male and female gametes and initiation of zygotic program. In the past few years, the molecular machineries underlying this biological process have been elucidated, particularly on the importance of synergid cells in pollen tube guidance, the Ca(++) spike as the immediate response of fertilization and the epigenetic regulation of parental gene expressions in early zygotic embryogenesis. This review outlines the most recent development in this area.

Apoptosis inhibition in ischemic brain by intraperitoneal PTD-BIR3-RING (XIAP).

Anti-apoptotic treatment is a promising strategy for neuroprotection against various brain injuries resulting from ischemia or neuron degeneration. X-linked inhibitor of apoptosis protein (XIAP) is regarded as the most effective apoptosis inhibitor, in which C-terminal structure BIR3-RING mainly inhibits caspase-9-dependent apoptosis. In the present study, we fused XIAP (BIR3-RING) to the protein transduction domain (PTD) of antennapedia homeodomain of Drosophila (Antp HD), and then used the oxygen glucose deprivation (OGD)-induced hippocampal slices injury in vitro, and the rat transient middle cerebral artery ischemia (tMCAO) models in vivo, to explore the anti-apoptotic effect of this recombinant protein. The results showed that the PTD could efficiently mediate the transduction of BIR3-RING into the hippocampal slices and rat brains. PTD-BIR3-RING could decrease OGD-induced cell death in brain slices (p < 0.05). Intraperitoneal injection of PTD-BIR3-RING could attenuate terminal deoynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) positive cells and decrease cleaved caspase-3 in the ischemic bounder zone compared with the control animals (p < 0.05). Further studies showed that ischemia-induced neurological outcomes were improved in rats with PTD-BIR3-RING treatment (p < 0.05). These results demonstrate that PTD-BIR3-RING could attenuate cell death in OGD hippocampal slices and decrease cell apoptosis in tMCAO brains through inhibiting of caspase-3 cleavage, suggesting that PTD-mediated protein transduction provides a novel and effective approach for the therapies of brain diseases such as cerebral ischemia.

[Analysis of CCM1 gene mutations in Chinese patients with intracranial cavernous malformations].

OBJECTIVE: To study the CCM1 gene (7q11.2 - q22) mutations in Chinese patients with intracranial cavernous malformations (ICM), METHODS: Peripheral blood samples were collected from 25 unrelated patients with ICM confirmed by post-operational pathology, 7 being with familial ICM, all of Han nationality, and from 30 healthy people as controls. The genomic DNA was extracted and the exons 8, 9, 11, 12, 13, 15, 16, 17, and 18 of CCM1 gene and part of intervening sequences near both sides of these exons were amplified by PCR. The PCR products were sequenced directly and then compared with the GenBank data. RESULTS: Seven new mutation sites of CCM1 gene were detected from 11 Chinese ICM patients with a total mutation rate of 44%. Of the seven new mutations there were three missense mutations: 1160A-->C (Q387P) and 1172C-->T (S391F) in exon12, and 1405A-->C (N469H) in exon13; two insertion mutations: 704insT (K246stop) in exon8, and 2138insG (T733stop) in exon18; one intervening sequence mutation: IVS12 - 4C-->T; and one synonymous mutation: 1875C-->T (F625F) in exon17. None mutation was detected in the control group. The CCM1 mutation rate of familial ICM was 85.7%, significantly higher than that of sporadic ICM (27.7%, P < 0.05). CONCLUSION: As the genetic basis of ICM, CCM1 gene mutation exists in Chinese ICM patients too, that leads to functional loss or changes of the gene encoding KRIT1 protein.

[New mutations of the 12th exon of CCM1 gene in Chinese patients with intracranial cavernous angiomas].

OBJECTIVE: To study the effect of CCM1 gene mutations in Chinese patients with intracranial cavernous angiomas(ICCA). METHODS: Twenty-one ICCA patients confirmed by pathology after operations in hospital from June 2002 to Feb.2003 and 15 healthy individuals as contrast were recruited. The peripheral venous blood samples of all the individuals were collected, and then DNA was extracted from the blood samples followed by amplification of exon 12 and some of its intron sequence using PCR. After purification, the PCR products were directly sequenced by ABI PRISM377 sequencing instrument. RESULTS: Three mutations of CCM1 gene were found in 5 patients and reported firstly. There existed a missense mutation of 1172C-->T in exon 12 in 5 patients, which led the No.391 amino acid of KRIT1 protein, serine, to phenyalanine. There existed a missense mutation of 1160A-->C in one patient, which led the No.387 amino acid, glutamine, to proline. Another mutation was an intronic mutation of IVS12-4C-->T in 4 patients. In contrast no mutations were found. CONCLUSION: The authors firstly report that mutations of CCM1 gene in exon 12 also exist in Chinese ICCA patients and those mutations are related with the occurring of ICCA.