Western blot analysis was used to investigate protein kinase C (PKC) profile of rat eggs. The presence of eight PKC isozymes was demonstrated: conventional PKC K K, L L and Q Q; novel PKC N N, O O and W W; atypical PKC j j and V V. PKC K K was detected by RT-PCR as well. PKC translocation from the cytosol to the plasma membrane served as a marker for enzyme activation. Immunofluorescence confocal microscopy demonstrated a relatively uniform distribution of PKC K K, L LI, and L LII throughout the cytosol of metaphase II arrested eggs. PKC accumulation at the plasma membrane was detected 5 min after exposure to 12-Otetradecanoyl phorbol-13-acetate and increased with time, thus demonstrating activation of these PKCs.z 1998 Federation of European Biochemical Societies.

The gene encoding the wild type Integrase protein of coliphage HK022 was integrated chromosomally and expressed in Arabidopsis thaliana plants. Double-transgenic plants cloned with the int gene as well as with a T-DNA fragment carrying the proper att sites in a tandem orientation showed that Int catalyzed a site-specific integration reaction (attP · attB) as well as a site-specific excision reaction (attL · attR). The reactions took place without the need to provide any of the accessory proteins that are required by Int in the bacterial host. When expressed in tobacco plants a GFP-Int fusion exhibits a predominant nuclear localization.

The gene copies for the alpha-subunit of the mitochondrial F1ATPase (atpA) were isolated and characterized in both male-fertile and cytoplasmic male sterile (CMS) petunia. Two copies, an intact gene and a truncated gene, were detected in both cytoplasms. The accumulated data, based upon a comparison of the sequences (the open reading frames as well as the 5' and 3' flanking regions) of the two atpA copies, both in male-fertile and CMS Petunia, indicate that: (1) they differ in their genomic organization and (2) a common progenitor cytoplasm, containing two copies of an intact atpA sequence, served as the origin for the atpA copies of the fertility and CMS-inducing cytoplasms. Homologous recombination through the progenitor intact atpA sequences is assumed to have caused the rearrangement in the 3' portion of the atpA open reading frame and the generation of the truncated atpA gene. It is thus suggested that the atpA pseudogenes, in both male-fertile and CMS cytoplasms, originated from a common progenitor atpA pseudogene sequence.

In petunia, a mitochondrial (mt) locus, S-Pcf, has been found to be strongly associated with cytoplasmic male sterility (CMS). The S-Pcf locus consists of three open reading frames (ORF) that are co-transcribed. The first ORF, Pcf, contains parts of the atp9 and coxII genes and an unidentified reading frame, urf-s. The second and third ORFs contain NADH dehydrogenase subunit 3 (nad3) and ribosomal protein S12 (rps12) sequences, respectively. The nad3 and rps12 sequences included in the S-Pcf locus are identical to the corresponding sequences on the mt genome of fertile petunia. In both CMS and fertile petunia, only a single copy of nad3 and rps12 had been detected on the physical map of the main mt genome. The origin of the urf-s sequence and the molecular events leading to the formation of the chimeric S-Pcf locus are not known. This paper presents evidence indicating that two different mt sequences, related to urf-s and found in fertile petunia lines (orf-h and Rf-1), might have been involved in the molecular evolution of the S-Pcf locus. Southern analysis of mtDNA derived from both fertile and sterile petunia plants suggests that one of these urf-s related sequences (showing 100% homology to urf-s and termed orf-h) is located on a sublimon. An additional, low-homology urf-s related sequence (Rf-1) is shown to be located on the main mt genome 5' to the nad3 gene. It is, thus, suggested that the sequence of events leading to the generation of the S-Pcf locus might have involved introduction of the orf-h sequence, via homologous recombination, into the main mt genome 5' to nad3 at the region where the Rf-1 sequence is located.

No abstract