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J M Jankowski

Publications and source records attributed to J M Jankowski.

At least 19 recordsLinked to original sources
PubMed1996

Regulation of protamine gene expression in an in vitro homologous system.

An in vitro transcription system from the trout testis nuclei was developed to study trout protamine gene expression. The protamine promoter contains, among others, two regulatory elements: 1) a cAMP-responsive element or CRE element (TGACGTCA) which is present in position 5' to TATA box, and 2) GC box (CCGCCC) which is present in position 3' to TATA box. The removal of the CRE-binding protein by titration (by the addition of appropriate oligonucleotides to the incubation mixture) resulted in a decrease in transcription of the protamine gene. These results were confirmed by experiments in which the pure CRE-binding factor (TPBP1) was used, as well as by those where a stimulatory effect of cAMP on protamine promoter transcription was observed. On the other hand, addition of oligonucleotides containing the GC-box sequence enhanced the protamine gene transcription indicating that the protein (Sp1 like) which binds to this sequence acts as a repressor of protamine gene expression. These results confirm the previously proposed model which suggested that the GC box played a role in negative regulation of the protamine gene expression. Involvement of some other factors in this process was also discussed.

Animals↗
PubMed1990

The N-terminal quarter of reovirus cell attachment protein sigma 1 possesses intrinsic virion-anchoring function.

Previously the receptor recognition domain of the reovirus serotype 3 (T3) cell attachment protein (sigma 1) was mapped to the C-terminal half of the protein using deletion mutagenesis of the reovirus S1 gene. A similar approach has been adopted in the present study to map the domain on T3 sigma 1 that is responsible for incorporation into the virion (i.e., the anchoring domain). Restriction enzymes which divide the T3 S1 cDNA into four segments (5'-I-II-III-IV-3') of similar size were used to generate four mutants, each with a particular segment deleted. The mutants were cloned into SV40 expression vectors and used to transfect COS-1 cells which were subsequently with reovirus serotype 1. Progeny viral particles with truncated T3 sigma 1 proteins incorporated were then identified by radioimmunoprecipitation with a serotype-specific anti-T3 sigma 1 serum. It was found that the mutant lacking I (mutant dl) was totally incapable of being incorporated into the virion, whereas the mutant lacking domain II (mutant dII) was incorporated efficiently. Due to altered antigenicities of the mutants lacking domain III (mutant dIII) or domain IV (mutant dIV), incorporation of these two proteins into virions was less detectable using the above assay. Evidence that domain I (the N-terminal 121 amino acids) alone dictates the incorporation of sigma 1 into the virion came from the subsequent demonstration that a chimeric protein containing domain I fused to chloramphenicol acetyltransferase (CAT) was incorporated into the virion (detectable with an anti-CAT serum) as efficiently as the full-length sigma 1 protein.

Animals↗
PubMed1987

The GC box as a silencer.

A DNA control sequence GTGGGCGGGGCAAT, or the "GC" box, has been described in the promoter regions upstream of a number of eukaryotic genes transcribed by polymerase II (for review, see Dynan, W.S. and Tjian, R., Nature 316:774, 1985). The "GC" box can occur in single or multiple copies and is the binding site for a protein factor, Sp1, which activates initiation of transcription. We have observed in the rainbow trout protamine gene 3' to the TATA box, three "GC" boxes spaced at 80 bp intervals. The first is 5' to the cap site and possesses the ability to "silence" transcription from the protamine promoter in constructs linking this promoter to the bacterial chloramphenicol acetyl transferase (CAT) coding sequence following transfection to COS-1 cells. A model is proposed to account for the silencing of the protamine gene in all tissues except developing sperm cells.

Animals↗
PubMed1986

In vitro expression of two proteins from overlapping reading frames in a eukaryotic DNA sequence.

The in vitro expression of two distinct proteins from overlapping reading frames in a sequence of rainbow trout genomic DNA has been demonstrated. In vitro transcription of DNA sequences, cloned in a plasmid under the control of Salmonella phage 6 polymerase promoter, led to the synthesis of two distinct and functional mRNAs corresponding to the protamine mRNA and also to another overlapping mRNA, termed Y. These mRNAs were translated in an mRNA-dependent rabbit reticulocyte lysate cell free system which synthesized the corresponding protein products. Similarities between the synthesized Pro-rich protein Y and three proline-rich proteins, the human salivary Pro-rich protein, the avian sarcoma virus protein P19 and the myc oncogene product, were evident and the significance of these findings is discussed. A synthetic oligonucleotide which is complementary to a sequence corresponding to a region of the Y protein mRNA, but upstream (5') of the transcribed protamine mRNA, hybridized faintly and only to trout brain RNA. However, more sensitive primer extension studies utilizing the Y-specific oligonucleotide detected several Y-related mRNAs in trout brain.

Amino Acid Sequence↗
PubMed1986

Evidence of sequences resembling avian retrovirus long terminal repeats flanking the trout protamine gene.

Additional TATA boxes are present in the flanking regions of trout protamine genes. Their activity as promoters was assayed using an in vitro transcription system. These additional TATA boxes, together with polyadenylation signals that include the consensus AATAAA and CACTG sequences very close to the promoters, suggest that these sequences may be closely related to retroviral long terminal repeat (LTR) sequences. Other features of retroviral LTRs that are also present are short inverted repeats. The LTR-like sequences flanking the trout protamine gene show significant homology to the avian sarcoma virus LTR over a 40-bp region. The trout protamine gene falls into the relatively rare intronless class of eukaryotic genes. This suggests that the gene could have been derived from a processed gene introduced into the genome by reverse transcription of a mature mRNA. The protamine-mRNA-coding region is flanked by AACA... TGTT sequences, which might represent vestigial traces of past recombination events and whose presence supports the notion that the protamine gene sequence was of foreign origin. Recent attempts in this laboratory to transfer the protamine gene into mouse cells have resulted in a high frequency of deletions similar to those observed with constructs in which a retrovirus was used as a vector to transfect foreign DNA with promoters. The distribution of protamine genes in the animal kingdom is very sporadic, which suggests that protamine genes appeared relatively late in evolution. The nonuniform occurrence of the gene among lower vertebrates may have been the result of its horizontal transmission only to certain species, possibly by infection with retroviruses that acquired it from a different species.

Animals↗
PubMed1985

Functional prokaryotic gene control signals within a eukaryotic rainbow trout protamine promoter.

Following the construction of a series of pSV2-cat derived plasmids containing the chloramphenicol acetyltransferase (CAT) gene under the control of a eukaryotic trout protamine promoter, it was noted that Escherichia coli, transformed with these plasmids, developed resistance to chloramphenicol (CM). This result suggested that the eukaryotic trout protamine promoter possessed significant prokaryotic promoter activity. Modification of the trout protamine promoter region by removing the region containing the eukaryotic Goldberg-Hogness box in the plasmid p525-cat increased the expression of the CAT gene almost to the wild-type level and conferred strong CM resistance. Sequence comparisons of the plasmid series indicate that prokaryotic promoter elements are present in the trout protamine promoter and that their similarity to the prokaryotic promoter consensus sequences and the distance between the two elements is more favourable in p525-cat, the plasmid which confers the greatest CM resistance.

Acetyltransferases↗
PubMed1985

The in vitro transcription of a rainbow trout (Salmo gairdnerii) protamine gene. II. Controlled mutation of the cap site region.

A series of plasmids containing new fusion genes in which the trout protamine gene is placed under the control of the complete herpes virus (HSV-1) tk promoter Pvu II-Bgl II fragment (pM8), or a shortened thymidine kinase (tk) promoter in which the region between the TATA box and the cap site is altered by using the Pvu II-Mlu I fragment (pM7), have been constructed. An additional recombinant plasmid was constructed in which the Bgl II-Ava II fragment of the protamine gene containing the entire protamine promoter but missing the protamine coding region was cloned into pBR322 between the Xho II 1666 and Hind III sites (pP5). For in vitro transcription, a HeLa cell lysate system was prepared and the RNA transcription products, after glyoxalation, were electrophoretically analyzed on 5% polyacrylamide gels. In constructing pM8 the DNA sequence between the tk promoter and the cap site was present while in pM7 it was deleted. Similar multiple transcripts were seen in both cases, indicating that the region between the promoter and the cap site has no effect upon transcription in vitro. The multiple transcripts appear to be due to the presence of a cryptic promoter in the complementary strand of the protamine gene. The activity of this cryptic promoter has been confirmed by comparison of the transcription of plasmid pP5, in which the protamine mRNA coding region has been deleted, with a previously described plasmid, pJBRP (Jankowski JM and Dixon GH (1984) Can. J. Biochem. Cell. Biol. 62, 291-300), containing the intact protamine gene.

Animals↗
PubMed1984

Transcription of a trout protamine gene in vitro: the effects of alteration of promoters.

An in vitro approach has been used to study trout protamine gene expression using various recombinant plasmids containing trout protamine genes as templates in the HeLa cell lysate transcription system. The specific RNA transcript which is protected against S1 nuclease digestion by hybridization to the protamine gene sequence is alpha-amanitin sensitive (1 micrograms/mL), showing that RNA polymerase II is involved. The sizes of transcripts from templates linearized with Bam HI, Rsa I, and Hpa II (all downstream from the putative TATA box) are consistent with those predicted from the known sequence of the protamine gene. Digestion at an Alu I site only 14 base pairs (bp) upstream from TATA box has no effect on the accuracy of transcription in vitro; however, cutting at an Ava II site 9 bp downstream from the TATA box (reading from the first T) abolishes transcription. Chimeric plasmids, in which a herpes simplex virus (HSV-1) thymidine kinase (tk) promoter is tandemly inserted upstream from the trout protamine DNA sequences or as a replacement of the natural protamine promoter, were constructed. Use of these plasmids allowed an examination in a single assay of eight different putative promoter sequences (TATAAAA, TATAAA, TACAAA, TATATA, TATTTAA, CATATTA, TATATTAT, and TATTTAT) that are localized in either the protamine or the tk genes. The canonical TATAAAA promoter (the natural protamine promoter) was the strongest one and, in its presence, none of the others were used significantly for transcription. However, when this promoter was removed the weaker promoters were able to promote transcription.

Animals↗
PubMed1976

[Recto-sigmoid carcinoma after uretero-sigmoidostomy. One case, with a review of the literature (author's transl)].

A case of recto-sigmoid adenocarcinoma, developing 25 years after bilateral uretero-sigmo dostomy for extrophia vesicae in a 29 year old man. A study of the literature emphasises the long delay before its appearance, the gastrointestinal nature of the tumour and its grave prognosis. The pathogenesis of this lesion is unknown at present, and consideration should be given to the effects of urine on the digestive mucosa and the role of a possible inflammatory granuloma, but also the possibility of a urinary tract origin, despite the apparent histological contradiction.

Adenocarcinoma↗