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PubMed1986

Evolutionary conservation of the substrate-binding cleft of phosphoglycerate kinases.

The primary structures of six phosphoglycerate kinases (PGKs) are known: three from mammals, one from yeast, and two from trypanosomes. Comparison of the amino acid sequence of these enzymes reveals 154 invariant positions out of 392 positions in the aligned sequences. Most of the conserved positions fall into the twelve beta-sheets and adjacent peptide regions that form the inner loops surrounding the ATP and 3-phosphoglycerate-binding cleft. The homology between mammalian and yeast PGKs is greater than 94% for the inner-loop region, even though the overall homology is less than 65%. Trypanosome PGK has only 44% overall homology with the mammalian enzyme, but shows 74% homology in the inner-loop region. Trypanosome PGK contains a polypeptide segment in its N-terminal domain that is transposed in comparison with the other species.

Amino Acid Sequence↗
PubMed1995

Sequence and evolutionary conservation of the murine Gbx-2 homeobox gene.

The homeobox gene family is divided into classes based on similarity of sequence across the homeodomain. Representative members of discrete classes are often conserved widely throughout evolution and this can extend to their genomic organisation and biological function. In this paper we report the first complete cDNA sequence of a member of the GBX class of homeobox genes, the murine gene Gbx-2. Sequence comparisons indicate that this homeodomain class is highly conserved within vertebrates. The homeodomain differs at only three positions out of 60 and these can be used to subdivide the GBX class homeodomains into 2 sub-classes.

Amino Acid Sequence↗
PubMed1995

Isolation and characterization of the cDNA for pea chloroplast SecA. Evolutionary conservation of the bacterial-type SecA-dependent protein transport within chloroplasts.

We report here the isolation of the cDNA for pea chloroplast SecA. Pea SecA encodes a polypeptide of 1,011 amino acids and shows high sequence similarity with cyanobacterial SecA. Pea SecA was synthesized as a larger precursor and was imported into isolated chloroplasts in vitro. The purified pea SecA, which was expressed in Escherichia coli cells, stimulated the in vitro import of the 33 kDa protein of the oxygen-evolving complex into thylakoids. These results indicate that higher plant chloroplasts contain a bacterial-type SecA protein-dependent system for the intraorganellar protein transport into thylakoids.

Adenosine Triphosphatases↗
PubMed1994

Transcriptional regulation of environmentally inducible genes in plants by an evolutionary conserved family of G-box binding factors.

1. In reviewing a number of the most intensely studied environmentally inducible promoters it becomes clear that the presence of two cis-acting elements are critical for promoter activity, one of which is the G-box (CCACGTGG). A mutation in one of the two elements abolishes or severely reduces the ability of the promoter to respond to environmental changes. The sequence of the second cis-acting element, positioned nearby the G-box, is not conserved among the different inducible promoters, but may be similar among promoters induced by the same signal. The spacing between the G-box and the second cis-acting element appears to be critical, suggesting a direct interaction between the respective binding factors. We speculate on a potential role of the G-box promoter element in the signal induction of promoter activity. 2. From a number of plant species nuclear proteins interacting with the G-box have been identified. Recently, G-box Binding Factors (GBF) have been isolated by screening cDNA expression libraries with a characterized G-box cis-acting element as DNA probe. The deduced amino acid sequence of the GBF clones revealed that they possess the features of the basic leucine zipper class of trans-acting factors. By amino acid sequence comparison and limited mutational analysis, we define amino acids critical for G-box binding specificity. All GBFs isolated to date have a conserved proline-rich domain involved in transcriptional activation. A number of GBFs are inducible by a particular environmental signal. 3. Recently, a protein designated GF14 has been isolated that is associated with the GBF protein complex. The protein has homology to mammalian brain specific proteins, which seem to function as regulators of phosphorylation events. GBF activity is regulated by phosphorylation. The GF14 proteins may therefore impose an additional control on gene expression.

Amino Acid Sequence↗
PubMedDate not supplied

An evolutionary conserved target cell antigen along with MHC class I molecules influences susceptibility to murine NK cell lysis.

We have previously characterized a novel monoclonal antibody (mAb), termed 18C2, which binds to and inhibits the lysis of target cells by human natural killer (NK) cells. We now show that the anti-target cell mAb 18C2 also recognizes a similar structure on the murine NK sensitive target cell YAC-1, as well as on NK resistant target cells P815 and EL-4, as observed by flow cytometry. Functional studies demonstrated that the mAb 18C2 inhibited the lysis of both NK sensitive YAC-1 target cells, as well as NK resistant target cell lines P815 and EL-4 by freshly-isolated nylon wool nonadherent (NWNA) NK cells, 5-day lymphokine activated killer (LAK) cells and adherent lymphokine activated killer (ALAK) cells. The inhibitory activity of the mAb 18C2 occurred at the target cell level only. Single cell conjugate assays as demonstrated that the structure recognized by the mAb 18C2 was involved in recognition between NK cells and NK target cells, as the mAb inhibited conjugate formation between a variety of effector cells and various target cell lines tested. Further, the role of major histocompatibility complex (MHC) class I antigens in NK cell cytotoxicity was examined. We observed that target cells expressing low levels of MHC class I antigens in association with the novel target cell antigen were more sensitive to NK cell lysis, as compared to cells that co-express higher levels of MHC class I antigen and the target cell antigen. Further, the presence of this antigen across different species suggests this target cell antigen/structure to be highly evolutionarily conserved.

Animals↗
PubMed1989

Evolutionary conservation of splice sites in sterile C mu transcripts and of immunoglobulin heavy chain (IgH) enhancer region sequences.

The immunoglobulin JHC mu intron was cloned from genomic DNA of a VHa3 rabbit and a 1257 bp sequence which contains conserved enhancer and splice sites was determined. From positions 315 to 1257, there is approximately 72 and 67% similarity to available sequences of man and mouse, respectively (counting gaps as single changes at single positions). In earlier studies of rabbit cDNAs encoding immunoglobulin heavy chains, we found a C mu-encoding cDNA clone (pB3) derived from splenic mRNA of a Trypanosome-hyperimmunized rabbit (VHa1) which lacked VH, DH or JH sequences and had an unknown sequence 5' of that encoding C mu. Comparison of this cDNA sequence with the present cloned genomic DNA sequence has now revealed that the start of cDNA pB3 corresponds to a position 80 base pairs 3' of the conserved octamer motif of the rabbit heavy chain enhancer. This mRNA was spliced to the acceptor site of C mu using a donor site which was 635 bp 3' of the enhancer octanucleotide. Our sequence of pB3 indicates that in rabbit as in mouse, a "nontron" (33 stop codons in three reading frames) can be formed utilizing a conserved splice site to produce a spliced transcript. The presence of evolutionarily conserved splice donor sites in the intron sequences of rabbit, mouse and man suggests a functional role during B cell ontogeny.

Animals↗
PubMed1995

The duck gene for alpha B-crystallin shows evolutionary conservation of discrete promoter elements but lacks heat and osmotic shock response.

The gene for alpha Beta-crystallin from a bird (the domestic duck, Anas platyrhynchos) has been cloned and sequenced to allow comparison with its mammalian homologues. The duck gene has the same general structure as those of humans and rodents although, unlike those of mammals, the duck gene has two polyadenylation signals at the 3' end. The most interesting comparisons are in the 5'flanking promoter regions. In contrast to the broad conservation of promoter sequence among mammals, only two significant blocks and a few smaller elements have been conserved during evolution in the more distantly related avian gene. Block 1 (-350/-308) corresponds to alpha BE-2, a functional element defined in the mouse gene. Further downstream, block 2 (-98/-65) shows 27/33 identity among all three species but does not correspond to any previously defined element. Other regions are less well-conserved. In particular, putative heat-shock response elements of the mammalian alpha B-crystallin genes are absent from the duck gene. In contrast to the heat and osmotic stress-inducibility of mouse alpha B-crystallin in NIH 3T3 cells, duck alpha B-crystallin showed no inducibility in duck cells in culture. Thus, although high expression in lens is common to alpha B-crystallin genes in birds and mammals, other modes of expression appear to be taxon-specific.

Amino Acid Sequence↗
PubMed1991

Evolutionary conservation of an epitope associated with striated rootlets in different epithelial ciliated cells.

In ciliated cells of metazoa, striated rootlets associated with basal bodies anchor the ciliary apparatus to the cytoskeleton. We have used here a monoclonal antibody against a 175 kDa protein associated with the striated rootlets of quail ciliated cells, to study ciliated cells of different species. In mussel gill epithelium the antibody recognized a protein of 92 kDa which shows a periodic distribution along the striated rootlets. In frog ciliated palate epithelium, two different rootlets are associated with basal bodies, both are decorated and only one protein of 48 kDa is recognized on immunoblot. The antigen is arranged in a helix around the striated rootlets. In rabbit ciliated oviduct epithelium, we detected the presence of very small and thin rootlets which are weakly labeled. We have shown that an epitope associated with the striated rootlets is preserved through evolution although the molecular weight of the peptide varies. We have also observed the appearance of this epitope on protein associated with junctional complexes in rabbit and cytoskeleton component in quail oviduct.

Animals↗
PubMed1989

Cloning and characterization of a cDNA for the B beta chain of rat fibrinogen: evolutionary conservation of translated and 3'-untranslated sequences.

A cDNA clone for the B beta chain of rat fibrinogen has been isolated and characterized. The cDNA insert is 1023 bp in length and corresponds to the 3' half of the B beta chain mRNA. The cDNA represents 890 bp of the coding sequence for the C-terminal half of the B beta chain and 133 bp of the 3'-untranslated region. The coding sequence for this region of the rat cDNA shares a high degree of identity with the corresponding regions of the human and bovine B beta-chain cDNAs and a moderate degree of identity with the corresponding region of the lamprey B beta-chain cDNA. A comparison of the amino acid sequences deduced from these cDNAs reveals three regions which share extensive identity among all four sequences. Two additional regions are identified which share extensive identity among the three mammalian sequences and significant identity with the lamprey sequence. These regions appear to represent distinct functional domains. Possible functions for these domains are briefly discussed. A high degree of identity also exists between the 3'-untranslated regions of the three mammalian cDNAs, suggesting that this region of the mRNA, although noncoding, is functionally important.

Amino Acid Sequence↗
PubMed1990

Evolutionary conservation of target sequences for cis-acting regulation in c-myc exon 1 and its upstream region.

Transcriptional control of the c-myc proto-oncogene, an important factor in cellular growth, differentiation and in the genesis of various neoplasms, is mediated by multiple positive and negative regulators in the 5' end region of the gene. Here, we report the nucleotide sequence of the first c-myc exon and its upstream region from woodchuck, a rodent which can develop liver tumors associated with c-myc activation [Möröy et al., Nature 324 (1986) 276-279]. Alignment of these sequences with the corresponding human and murine regions shows a surprisingly high homology between woodchuck and human, and suggests the absence of species-specificity in the fundamental regulatory elements which govern c-myc expression.

Animals↗
PubMed1991

Structure, chromosomal localization and evolutionary conservation of the gene encoding human U1 snRNP-specific A protein.

Three specific proteins, called A, 70K and C, are present in the U1 small nuclear ribonucleoprotein (snRNP) particle, in addition to the common proteins. The human U1 snRNP-specific A protein is, apart from a proline-rich region, highly similar to the U2 snRNP-specific protein B". To examine the homologous regions at the genomic level, we isolated and characterized the human U1-A gene. The human U1-A protein appears to be encoded by a single-copy gene and its locus has been mapped to the q arm of chromosome 19. The gene, about 14-16 kb in length, consists of six exons. The regions homologous to the U2-B" gene are not limited to single exons and are mostly not confined by exon-exon junctions in the corresponding U1-A mRNA. However, the proline-rich region of U1-A, absent in U2-B", is encoded by a single exon, suggesting a specific function for this domain of U1-A. The region of the cap site and upstream sequences contain interesting similarities to the promoter region of other snRNP protein-encoding genes and several housekeeping genes, in particular the vertebrate ribosomal protein-encoding genes. Hybridization experiments with various vertebrate genomic DNAs revealed that U1-A sequences are evolutionarily conserved in all tested vertebrate genomes, except for chicken, duck and pigeon. The divergence of these avian genomes is probably typical for the class of birds.

Amino Acid Sequence↗
PubMed1995

Evolutionary conservation in the DNA-binding and -bending properties of HMG-boxes from SRY proteins of primates.

Mammalian sex determination is caused by the Y-chromosome gene SRY, which encodes a protein containing a DNA-binding domain (HMG-box) of about 70 amino acids (aa). The HMG-box is very conserved in a wide variety of mammals; conversely, the flanking non-box regions show a high degree of aa sequence divergence, even between closely related species. The HMG-box of human SRY binds sequence-specifically to linear DNA and produces a sharp bend; it also interacts with high affinity to kinked DNA structures irrespective of their sequences. Point mutations associated with sex reversal in XY human females fall within the HMG-box and either affect the affinity for DNA or modify the geometry of the DNA-protein complex. Here, we show that the DNA-binding and -bending properties of the HMG-boxes of SRY from human and seven different primates are extremely similar to each other. Together with other data, this suggests that the inability of mouse and human SRY to substitute for each other is due to differences in the conserved HMG-box, rather than the non-conserved flanking sequences.

Amino Acid Sequence↗