Expressed sequence tags analysis of Blattella germanica

Four hundred and sixty five randomly selected clones from a cDNA library of Blattella germanica were partially sequenced and searched using BLAST as a means of analyzing the transcribed sequences of its genome. A total of 363 expressed sequence tags (ESTs) were generated from 465 clones after editing and trimming the vector and ambiguous sequences. About 42% (154/363) of these clones showed significant homology with other data base registered genes. These new B. germanica genes constituted a broad range of transcripts distributed among ribosomal proteins, energy metabolism, allergens, proteases, protease inhibitors, enzymes, translation, cell signaling pathways, and proteins of unknown function. Eighty clones were not well-matched by database searches, and these represent new B. germanica-specific ESTs. Some genes which drew our attention are discussed. The information obtained increases our understanding of the B. germanica genome.

Purification and Characterization of Novel Genes of Human Fetal Astrocytes

Astrocytes are ubiquitous in the brain and have multiple functions. It is becoming clear that they play an important role in monitoring the neuromicroenvironment, information processing, and signaling in the central nervous system (CNS) in normal conditions and respond to CNS injuries. During the development of the CNS, astrocytes play a key role as a substrate for neuronal migration and axonal growth. To identify genes that could participate in astrocyte maturation, we used the differential display reverse transcription-PCR (DDRT-PCR) method. Human fetal astrocytes were cultured and total RNAs are isolated at intervals of 5 days for 50 days. Using 24 primer combinations, we have identified a set of 18 candidate cDNAs deriving from excised DDRT-PCR bands. DNA sequencing revealed 16 genes that have been described already (HMGCR, thyroid receptor interactor gene, NPM, transglutaminase mRNA, and SPARC etc.). We have also found two novel genes (A3 and C8), which were expressed differently in culture stages. A3 expressed decreasingly and C8 expressed increasingly in accordance with to culture stages. We have analysed these two genes. A3 (3,626 bp) showed 93% homology with the Homo sapiens general transcription factor 3 (GTF3) and C8 (2,401 bp) had 97% homology with the transmembrane receptor Unc5H2. Temporal expression of these two genes in this study suggests that the proteins of these genes may have different roles in maturation of the human fetal astrocytes.

Molecular Cloning of Novel Genes Related to the Craniofacial Development of Human Embryo

In order to obtain novel genes for craniofacial development of human, molecular cloning and sequencing were performed and followed by in situ hybridization in tissue sections. Subtracted cDNA library of craniofacial tissue from 8 weeks old human embryo was made by the subtraction with cDNA of RHEK cells. A total of 231 clones were obtained and their partial sequence data disclosed that 214 clones were nonredundant in Genebank search. We have done in situ hybridization screening on the craniofacial sections of a 10 weeks old human fetus, and found significant positive reaction in 30 clones. Depending on the cell type of similar developmental origin, the positive reactions could be divided into four groups: first group showed an intense positive reaction in neural tube, ganglion, and a part of peripheral nerve tissue, second group relatively diffuse positive reaction in neural tube, cartilage, epithelium, and muscle, third group localized positive reaction in nerve, and muscle, and fourth group positive reaction in almost all kinds of cells of craniofacial tissues. Although every clone showed different expression patterns in the craniofacial development, some of them showed intense mRNA expressions in the characteristic cell type. Because this study also aimed to test a screening methods to find out novel genes related to craniofacial development by the subtracted cDNA library and in situ hybridization, the intense positive reaction of a certain clone by in situ hybridization may indicate its role in the developmental processes. We presumed that 30 clones selected in this study are possibly important new genes for the development of human craniofacial structure.