Characterization of a chicken polyubiquitin gene preferentially expressed during spermatogenesis.

We have previously reported that a chicken polyubiquitin gene (Ub II) not expressed under normal or heat shock conditions in chick fibroblasts is transcribed during spermatogenesis [(1987) Nucleic Acids Res. 15, 9604]. The level of Ub II mRNA is several-fold higher in testis cells than in somatic tissues. The gene Ub II possesses characteristic features not seen in the polyubiquitin gene expressed in heat shock conditions (Ub I). The 5' noncoding region of Ub II shows the consensus cAMP regulatory element (CRE) followed immediately downstream by a CA dinucleotide. It has been proposed that this extended CRE may be involved in the coordinate expression of various genes during spermatogenesis.     

Organization and chromosomal localization of the gene for the human bombesin receptor subtype expressed in pregnant uterus

The gene encoding the human homologue of the guinea pig uterine bombesin receptor [(1992) Eur. J. Biochem. 208,405] was isolated from a genomic lambda library by the PCR/homology screening approach. The gene spans more than 4 kb and consists of 3 exons and 2 introns. The deduced amino acid sequence shows about 86% identity to that of guinea pig bombesin receptor. This subtype of bombesin receptor is expressed in the pregnant uterus and in two human tumour cell lines, T47D (ductal breast carcinoma) and A431 (epidermal carcinoma). PCR analysis of genomic DNA from human-mouse cell hybrids allows the cloned gene to be localized to the region q26–q28 on chromosome X.     

Organization and chromosomal localization of the human interleukin 5 receptor alpha-chain gene.

The gene for the hIL-5R alpha subunit, which is present in a single copy in the human genome, has been analysed in detail. It is located on chromosome 3 in the region 3p26. The gene organization reflects its relationship to the cytokine/haematopoietin receptor superfamily. Three introns are located in the 5' untranslated region. The subsequent exons determine the functional domains of the hIL-5R alpha protein: the signal peptide, three fibronectin type III-like (FN-like) modules, each built up by two exons, the membrane anchor and two exons forming the cytoplasmic tail, the first of which contains the proline cluster region. In addition, a specific exon generating a soluble isoform is located before the membrane anchor exon. This specific exon contains an in frame TAA stop codon, followed by a polyadenylation signal. Hence, a normal splicing event leads to a soluble IL-5R alpha variant, whereas alternative splicing is required for cell membrane anchoring. A second area of alternative splicing is found in the 5' leader sequence, and possibly relates to the presence of short open reading frames preceding the main ATG. All intron-exon junctions meet the GT-AG rule. The gene structures of all cytokine/haematopoietin receptors documented so far have also been compared with respect to intron phasing. This shows that all introns between the FN-III-like modules are of the +1 type, but in addition, splice sites within the Cys-module and WS-WS-module are invariably of the +2 and 0 type, respectively.     

Sequence and expression of testis-expressed gene 14 (Tex14): a gene encoding a protein kinase preferentially expressed during spermatogenesis

To discover germ cell-specific genes, we used in silico subtraction and identified testis expressed gene 14 (Tex14). Mouse Tex14 contains an open reading frame encoding a 1450-amino-acid protein, which shares 64% amino acid identity with the predicted human TEX14 protein. The predicted TEX14 amino acid sequence consists of three ankyrin repeats, a protein kinase domain, and a leucine zipper dimerization motif. Northern blot analysis and in situ hybridization show that Tex14 mRNA is expressed specifically in the testis, with highest levels observed in pachytene, diplotene, and meiotically dividing spermatocytes. Two 5' splice variants of mouse Tex14 were discovered by sequencing 5'-RACE polymerase chain reaction products. TEX14 is predicted to be localized to the nucleus, suggesting that it may play a key role in regulating gene expression or modulating nuclear events during mammalian spermatogenesis.     

Sequence analysis, and chromosomal localization of a gene encoding a cystatin-like protein from Drosophila melanogaster.

Using polyclonal antibodies raised against a Drosophila Ca2(+)-binding protein (DCABP-23), clones were isolated from a Drosophila head cDNA library constructed in the expression vector lambda gt11. Two non-homologous clones have been isolated and are being subjected to sequence analysis. One of these clones, though not encoding DCABP-23, does encode a Drosophila cystatin-like protein. This presumed Drosophila cystatin shows homology to mammalian cystatins, chicken egg white cystatin and the rice oryzacystatin. The Drosophila cystatin has been mapped, by in situ hybridization, to region 88C on the right arm of the third chromosome.     

Structure and chromosomal localization of the gene encoding barley seed peroxidase BP 2A.

A clone, lambda Prx6.1, coding for a barley seed peroxidase (BP; EC 1.11.1.7), was isolated from a genomic library using a cDNA coding for the barley seed peroxidase, BP 1, as a probe. The nucleotide sequence coded for a BP showing 73% amino acid (aa) sequence identity with BP 1 and less than 50% similarity with other sequenced plant peroxidases. The aa composition is 92% identical to that determined for BP 2 purified from mature barley grains, and therefore the gene product is named BP 2A. The alignment suggests that the coding region is interrupted by a 76-bp intron having the consensuses GT and AG, at the 5' and 3' ends, respectively. Alignment with BP 1 suggests that BP 2A has a leader peptide of 36 aa and the mature protein is 319 aa. Alanine and leucine account for 50% of the residues of the leader peptide. Of the codons used 90% have a C or G in the third position. The promoter shows a putative abscisic acid-response element, 5'-GTACGTGTC, 115 bp upstream from the start codon. The BP 2A-encoding gene was RFLP-mapped on barley chromosome 3, and we suggest for this peroxidase locus the name Prx6.