Molecular Cloning and Characterization Analysis of Phosphofructokinase Gene from Dunaliella parva

Phosphofructokinase (PFK), which catalyses the phosphorylation of fructose-6-phosphate to fructose-1,6- bisphosphate, a key regulatory step in the glycolytic pathway. The former studies indicated the PFK could enhance glycolysis. The full-length cDNA encoding PFK was obtained from oleaginous microalgae Dunaliella parva, which include 1572 bp open reading frame (ORF), 254 bp 5′-untranslated sequence and 323 bp 3′-untranslated sequence. Dunaliella parva PFK showed the highest sequence similarity with the PFK from Chlamydomonas reinhardtii and Volvox carteri. The Dunaliella parva PFK also showed wide similarity with other species.

Molecular Cloning and Characterization Analysis of 3,8-Divinyl Protochlorophyllide a 8-Vinyl Reductase Gene from Dunaliella parva

The vast majority of photosynthetic organisms utilize monovinyl chlorophyll for their photosynthetic reactions. For the biosynthesis of monovinyl chlorophyll, the reduction of the 8-vinyl group which is located on the B-ring of the macrocycle is essential. 3,8-Divinyl protochlorophyllide a 8-vinyl reductase (DVR) catalyzes the reduction of 8-vinyl group on the tetrapyrrole to an ethyl group, which is necessary for monovinyl chlorophyll (Chl) synthesis. The former studies indicated the DVR could enhance photosynthesis. The full-length cDNA encoding DVR was obtained from oleaginous microalgae Dunaliella parva, which include 1326 bp open reading frame (ORF), 22 bp 5′-untranslated sequence and 383 bp 3′-untranslated sequence. Dunaliella parva DVR showed the highest sequence similarity with the DVR from Chlamydomonas reinhardtii and Volvox carteri. The Dunaliella parva DVR also showed wide similarity with other species.

Molecular Cloning and Characterization Analysis of Low CO2–Inducible Protein Gene from Dunaliella parva

Microalgae could modulate their photosynthesis to acclimate to CO2-limiting stress through inducing a carbon-concentrating mechanism (CCM) which included carbonic anhydrases and inorganic carbon (Ci) transporters. However, Ci-specific transporters have not been well described in algae so far. The former studies indicated that low CO2-inducible protein (Lci) played a significant role in the CCM, could increase Ci uptake and intracellular Ci accumulation under low CO2 conditions. The full-length cDNA encoding Lci was obtained from oleaginous microalgae Dunaliella parva, which include 1302 bp open reading frame (ORF), 255 bp 5′-untranslated sequence and 447 bp 3′-untranslated sequence. Similarity analysis revealed that the highest identity was found among Dunaliella parva, Chlamydomonas reinhardtii and Volvox carteri. The Dunaliella parva Lci also showed wide similarity with other species.

Molecular Cloning and Characterization Analysis of Malic Enzyme Gene from Dunaliella parva

Malic enzymes are a class of oxidative decarboxylases which catalyze the oxidative decarboxylation of malate to pyruvate and carbon dioxide. the former studies on lipid pathways and genetic engineering test for enhanced lipid synthesis suggests that ME are the most promising targets gene for enhanced lipid synthesis. The full-length cDNA encoding NADP malic enzyme was obtained from oleaginous microalgae Dunaliella parva, which include 1293 bp open reading frame (ORF) and 26 bp 3′-untranslated sequence. NCBI-CD search revealed that there are two mainly domains predicted in the Dunaliella parva ME protein. In addition, a 724 bp promoter was obtained. The potential regulatory elements associated with hormone and light responses were also found in the ME promoter region. Similarity analysis revealed that the highest identity was found between Dunaliella parva and Chlamydomonas reinhardtii. The Dunaliella parva ME also showed wide similarity with other species.

CDC73/HRPT2 CpG island hypermethylation and mutation of 5′-untranslated sequence are uncommon mechanisms of silencing parafibromin in parathyroid tumors

The tumor suppressor HRPT2/CDC73 is mutated in constitutive DNA from patients with the familial disorder hyperparathyroidism–jaw tumor syndrome and in ∼70% of all parathyroid carcinomas. In a number of HRPT2 mutant tumors however, expression of the encoded protein parafibromin is lost in the absence of a clear second event such as HRPT2 allelic loss or the presence of a second mutation in this tumor suppressor gene. We sought to determine whether hypermethylation of a 713 bp CpG island extending 648 nucleotides upstream of the HRPT2 translational start site and 65 nucleotides into exon 1 might be a mechanism contributing to the loss of expression of parafibromin in parathyroid tumors. Furthermore, we asked whether mutations might be present in the 5′-untranslated region (5′-UTR) of HRPT2. We investigated a pool of tissue from 3 normal parathyroid glands, as well as 15 individual parathyroid tumor samples including 6 tumors with known HRPT2 mutations, for hypermethylation of the HRPT2 CpG island. Methylation was not identified in any specimens despite complete loss of parafibromin expression in two parathyroid carcinomas with a single detectable HRPT2 mutation and retention of the wild-type HRPT2 allele. Furthermore, no mutations of a likely pathogenic nature were identified in the 5′-UTR of HRPT2. These data strongly suggest that alternative mechanisms such as mutation in HRPT2 intronic regions, additional epigenetic regulation such as histone modifications, or other regulatory inactivation mechanisms such as targeting by microRNAs may play a role in the loss of parafibromin expression.