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PubMed2001

The stress- and abscisic acid-induced barley gene HVA22: developmental regulation and homologues in diverse organisms.

Abscisic acid (ABA) induces the expression of a battery of genes in mediating plant responses to environmental stresses. Here we report one of the early ABA-inducible genes in barley (Hordeum vulgare L.), HVA22, which shares little homology with other ABA-responsive genes such as LEA (late embryogenesis-abundant) and RAB (responsive to ABA) genes. In grains, the expression of HVA22 gene appears to be correlated with the dormancy status. The level of HVA22 mRNA increases during grain development, and declines to an undetectable level within 12 h after imbibition of non-dormant grains. In contrast, the HVA22 mRNA level remains high in dormant grains even after five days of imbibition. Treatment of dormant grains with gibberellin (GA) effectively breaks dormancy with a concomitant decline of the level of HVA22 mRNA. The expression of HVA22 appears to be tissue-specific with the level of its mRNA readily detectable in aleurone layers and embryos, yet undetectable in the starchy endosperm. The expression of HVA22 in vegetative tissues can be induced by ABA and environmental stresses, such as cold and drought. Apparent homologues of this barley gene are found in phylogenetically divergent eukaryotic organisms, including cereals, Arabidopsis, Caenorhabditis elegans, man, mouse and yeast, but not in any prokaryotes. Interestingly, similar to barley HVA22, the yeast homologue is also stress-inducible. These observations suggest that the HVA22 and its homologues encode a highly conserved stress-inducible protein which may play an important role in protecting cells from damage under stress conditions in many eukaryotic organisms.

Abscisic Acid↗

PubMed2002

Developmental regulation and downstream effects of the knox class homeobox genes Oskn2 and Oskn3 from rice.

Plant homeobox genes of the class 1 knox (knotted1-like) type are involved in the regulation of shoot apical meristem formation and function. Their expression generally occurs either throughout the meristem or specifically at the lateral organ boundaries. Down-regulation in the organ primordia is tightly controlled and misexpression in leaves leads to a perturbed development. Here, the transcriptional control of two rice knox genes, Oskn2 and Oskn3, was addressed, showing that the promoter sequences of both genes mediate the initial down-regulation during lateral organ formation, but are insufficient to keep expression in lateral organs stably off. Therefore, maintenance of the repressed state requires control elements outside the promoter regions. Ectopic expression of Oskn2 or Oskn3 induced similar defects in panicle branching. internode elongation and leaf patterning. However, small differences suggested that their target gene specificities are not completely overlapping. This was supported by the observation that Oskn3 protein but not Oskn2 could interact with two reported recognition sequences of a KNOX protein from barley. Finally, protein-protein interactions may contribute to the functioning of KNOX proteins, as the ability of Oskn3 and Oskn2 to form heterodimers could be demonstrated.

DNA, Plant↗

PubMed2002

Characterization of a tissue-specific and developmentally regulated beta-1,3-glucanase gene in pea (Pisum sativum).

As part of a search for seed coat-specific expressed genes in Pisum sativum cv. Finale by PCR-based methods, we identified and isolated a cDNA encoding a beta- 1,3-glucanase, designated PsGNS2. The deduced peptide sequence of PsGNS2 is similar to a subfamily of beta-1,3-glucanases, which is characterized by the presence of a long amino acid extension at the C-terminal end compared to the other beta-1,3-glucanases. PsGNS2 is expressed in young flowers and in the seed coat and is weakly expressed in vegetative tissues (roots and stems) during seedling development. It is not inducible by environmental stress or in response to fungal infection. In developing pea flowers the transcript is detectable in all four whirls. In the seed coat the expression is temporally and spatially regulated. High abundance of the transcript became visible in the seed coat when the embryo reached the late heart stage and remained until the mid seed-filling stage. In situ hybridization data demonstrated that the expression of PsGNS2 is restricted to a strip of the inner parenchyma tissue of the seed coat, which is involved in temporary starch accumulation and embryo nutrition. This tissue showed also less callose deposits than the other ones. The 5' genomic region of PsGNS2 was isolated and promoter activity studies in transgenic Medicago truncatula showed a seed-specific expression. Highest activity of the promoter was found in the seed coat and in the endosperm part of the seed.

Amino Acid Sequence↗

PubMed2002

Inducibility by pathogen attack and developmental regulation of the rice Ltp1 gene.

Using a genomic clone encoding a rice lipid transfer protein, LTP1, we analysed the activity of the 5' region of the Ltp1 gene in transgenic rice (Oryza sativa L.) during plant development and under pathogen attack. The -1176/+13, -556/+13 and -284/+13 regions of the promoter were fused upstream from the uidA reporter gene and nos 3' polyadenylation signal, resulting in the pdelta1176Gus, pdelta556Gus and pdelta284Gus constructs which were transferred to rice by microprojectile bombardment. Histochemical and fluorometric GUS assays and in situ detection of uidA transcripts in transgenic homozygous lines harbouring the pdelta1176Gus construct demonstrated that the Ltp1 promoter is preferentially active in aerial vegetative and reproductive organs and that both specificity and level of expression are regulated during organ development. In leaf sheath, GUS activity which is initially strictly localized in the epidermis of growing tissue, becomes restricted to the vascular system in mature tissues. In expanded leaf blade, expression of the uidA gene was restricted to the cutting level suggesting inducibility by wounding. Strong activity was detected in lemma and palea, sterile glumes, and immature anther walls and microspores but not in female reproductive organs. No GUS activity was detected during seed embryo maturation whereas the uidA gene was strongly expressed at early stages of somatic embryogenesis in scutellum tissue. The Ltp1 transcripts were found to strongly accumulate in response to inoculation with the fungal agent of the blast disease, Magnaporthe grisea, in two rice cultivars exhibiting compatible or incompatible host-pathogen interactions. Analysis of pdelta1176Gus leaf samples inoculated with the blast fungus demonstrated that the Ltp1 promoter is induced in all cell types of tissues surrounding the lesion and notably in stomata guard cells. In plants harbouring the Ltp1 promoter deletion construct pdelta556Gus, activity was solely detected in the vascular system of mature leaves whereas no uidA gene expression was observed in pdelta284Gus plants. These observations are consistent with the proposed role of LTP1 in strenghtening of structural barriers and organ protection against mechanical disruption and pathogen attack.

Antigens, Plant↗

PubMed1998

Developmental regulation of protein phosphatase types 1 and 2A in post-hatch chicken brain.

The activity and subcellular distribution of protein phosphatases 1 and 2A were measured in chicken forebrain and cerebellum during post-hatch development. At all post-hatch ages, a large proportion of PP1 and PP2A was membrane bound and these enzymes were less active than their cytosolic counterparts. The protein concentration of PP1 in the membranes increased 40% between 2 and 14 days and a further 60% between 14 days and adult, whereas the PP1 enzyme activity in the membranes progressively decreased. In contrast to PP1, the protein concentration of PP2A remained constant in all fractions during post-hatch development, and the enzyme activity of PP2A did not change except for a decrease in the membrane-bound activity between 2 and 14 days. These results show that the subcellular distribution and activity of PP1 is selectively regulated during post-hatch development and that membrane association and inactivation of PP1 are independent events.

Aging↗

PubMed1998

Human Wnt-13 is developmentally regulated during the differentiation of NTERA-2 pluripotent human embryonal carcinoma cells.

The Wnt gene family encodes a series of conserved glycoproteins that regulate pattern formation during embryogenesis, in a variety of tissues including the nervous system. As with other genes that control embryonic cell differentiation, members of the Wnt family have also been implicated in tumourigenesis. To search for Wnt genes involved in human teratocarcinomas, with a possible role in human embryogenesis, we used RT-PCR primed with degenerate oligonucleotides to analyse mRNA from differentiating cultures of the pluripotent human embryonal carcinoma (EC) cell line NTERA-2. NTERA-2 EC cells differentiate into neurons and other cell types when induced with retinoic acid. Wnt gene expression was not detected in the undifferentiated EC cells, but Wnt-related PCR fragments were amplified from differentiating cultures, 4-14 days after induction with retinoic acid. The RT-PCR products were composed primarily of DNA fragments corresponding to the recently identified human Wnt-13 gene. No other Wnt-related genes were identified. Northern analysis confirmed induction of Wnt-13 as a 2.4 kb mRNA during the early phases of retinoic acid-induced differentiation, and during differentiation along a non-neural pathway induced by hexamethylene bisacetamide (HMBA), but not in the terminally differentiated neurons. Wnt-13 remained expressed in non-neural differentiated NTERA-2 cells, even several weeks after the induction of differentiation. The time course of induction, its induction by HMBA, and its persistence in differentiated cells indicate that Wnt-13 expression is not dependent upon direct activation by retinoic acid. Wnt-13 was not detected, or only detected at low levels, in other human EC cells. However, it was found to be expressed at a high level in one malignant teratoma cell line, 577MF, that does not exhibit an EC phenotype although it was derived from a testicular teratocarcinoma. At least two members of the human frizzled gene family, thought to encode receptors for Wnt proteins, were also expressed in the NTERA-2 cells, suggesting the presence of a mechanism by which endogenously expressed Wnt-13 could modulate the histogenesis of teratocarcinomas by mediating interactions between sub-populations of differentiating EC cells. We note that Wnt-13 maps to chromosome 1p13, a region reported to be subject to relatively frequent loss of heterozygosity in germ cell tumours. Further analysis indicated that 465 bp of the published Wnt-13 sequence, within the predicted 5' UTR, is incorrect and is possibly derived from a human mitochondrial DNA sequence.

Acetamides↗

PubMed1995

Developmental regulation of ribosomal protein L16 genes in Arabidopsis thaliana.

Lateral roots can be synchronously induced in Arabidopsis by a brief auxin treatment. An early event in the development of a lateral root primordium is the accumulation of mRNAs encoding ribosomal proteins. In situ hybridizations show that mRNA encoding one ribosomal protein, L16, accumulates in all rapidly proliferating tissues including the shoot and root apical meristems and lateral root primordia. To understand further the mechanisms by which ribosomal proteins are coordinately synthesized, two genes encoding the ribosomal protein L16 were isolated from Arabidopsis thaliana. Promoter sequences from each RPL16A and RPL16B were fused to the beta-glucuronidase reporter gene GUS. The promoter of RPL16B(from -848 to -19) conferred X-Gluc staining in proliferating tissues including the shoot and root apical meristems. When GUS was expressed from the RPL16A promoter (from -875 to -22), X-Gluc staining was observed in cells in the root stele and in anthers. When seedlings transformed with either promoter construct were treated with auxin to induce lateral roots, X-Gluc staining accumulated in the lateral root primordia by 16 h after induction. Transcription of the RPL16B promoter appears to be correlated with cell division, while transcription of the RPL16A promoter is very cell specific. Expression of two genes encoding L16 during the early phase of lateral root initiation and in developing pollen may serve to increase levels of ribosomal proteins during the rapid growth of these tissues.

Amino Acid Sequence↗

PubMed1997

Developmental regulation of the gibberellin biosynthetic gene GA1 in Arabidopsis thaliana.

The GA1 gene of Arabidopsis thaliana encodes ent-kaurene synthase A (KSA), which catalyzes the first committed step in the biosynthetic pathway of the plant hormone gibberellin (GA). Its location in the GA biosynthetic pathway has led to speculation that KSA regulation is one of the controlling steps. However, because KSA activity is so low that it is only measurable in Arabidopsis siliques, GA1 promoter-GUS reporter gene fusions and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) were used to examine the expression pattern of GA1. The results from this study indicate that GA1 gene expression is highly regulated during growth and development, and it is restricted to specific cell types at the sites of expression. GA1 promoter activity is highest in rapidly growing tissues, e.g. shoot apicas, root tips, developing flowers and seeds. It is also active in the vascular tissue of some non-growing organs, such as expanded leaves, suggesting that these leaves may be a site of GA synthesis for transport to other organs. It was also found that the first one or two introns in the GA1 gene are required for proper expression. Because of the high degree of regulation, GA1 may act as a gatekeeper, controlling the flow of metabolites into the GA biosynthetic pathway, while the levels of specific bioactive GAs are controlled by other downstream steps.

Alkyl and Aryl Transferases↗

PubMed1997

Developmental regulation of a plant encoded inhibitor of eukaryotic initiation factor 2 alpha phosphorylation.

An inhibitor of eIF-2a phosphorylation was identified in various plant species. The plant protein (termed PKI) specifically cross-reacts with monoclonal antiserum that recognizes the glycosylated, active form of a M(r) 87 kD protein analog (p67) from reticulocytes. Northern blot analysis using a probe to the reticulocyte inhibitor cDNA further supports the presence of analogous transcripts in plant tissue. PKI specifically inhibits the phosphorylation of the plant encoded eIF-2 alpha kinase (pPKR) as well as plant and human eIF-2 alpha phosphorylation. The interaction between PKI and pPKR is indicated by their copurification on dsRNA agarose, despite evidence showing that PKI does not bind dsRNA. Further, wheat PKI inhibits human PKR phosphorylation but activity is recovered by immuno-depletion of PKI from wheat germ fractions. PKI is temporally regulated during plant growth and development. It is maximally present in extracts from dormant seeds, however, it is not detectable soon after leaf emergence at approximately 48 h post-imbibition. PKI levels are again detectable at the mid-milk stage in seed development. Protein levels of pPKR in ribosomal salt wash and cytosolic extracts from healthy plant tissue remain essentially constant throughout the life cycle. In contrast, pPKR activity levels based upon autophosphorylation vary significantly and are inversely correlated with PKI protein levels. Phosphorylation of eIF-2 alpha is a classical mechanism for the downregulation of protein synthesis suggesting that inhibition of pPKR activity by PKI may contribute to the dramatic and rapid increase in protein synthesis observed during seed germination.

Antibodies, Monoclonal↗

PubMed1999

A novel parsley 4CL1 cis-element is required for developmentally regulated expression and protein-DNA complex formation.

The phenylpropanoid enzyme 4-coumarate:coenzyme A ligase (4CL) participates in the biosynthesis of a wide range of secondary products with specialized function and tissue distribution in plants. The parsley 4CL1 promoter directs a complex tissue- and cell-specific pattern of reporter gene expression in transgenic tobacco, consistent with the distribution of phenylpropanoid products and sites of 4CL expression in tobacco vegetative and floral organs. We generated mutants in a 4CL1 promoter element previously implicated as a site for protein-DNA complex formation to analyze its role in vivo. Mutation of this element (FP56) reduced expression in some organs/tissues up to several hundredfold, with little effect on cell-specific expression patterns. Electrophoretic mobility shift assays indicated that the FP56 cis-element is the binding site for tobacco and parsley nuclear proteins, and that mutations in the same element that reduce reporter gene expression in transgenic plants greatly reduce or abolish protein-DNA complex formation. DNAse I protection assays showed that the region of the 4CL1 promoter surrounding the FP56 element is the site for formation of two large protein-DNA complexes, and that an intact FP56 element is required for formation of these complexes. Finally, the detergent deoxycholate was used to investigate the role of protein-protein interactions in FP56 complex formation. Our data suggest that the FP56 cis-element plays a central role in transcriptional activation from the 4CL1 promoter, and that its role may be to nucleate formation of a large protein complex on the promoter.

Apiaceae↗

PubMed1995

Developmental regulation of expression and activity of multiple forms of the Drosophila RAC protein kinase.

We have characterized the Drosophila homologue of the proto-oncogenic RAC protein kinase (DRAC-PK). The DRAC-PK gene gives rise to two transcripts with the same coding potential, generated by the use of two different polyadenylation signals. Each transcript encodes two polypeptides because of the presence of a weaker initiator ACG codon, upstream from the major AUG, such that the larger protein contains an N-terminal extension. Like the human isoforms, DRAC-PKs possess a novel signaling region, the pleckstrin homology domain. DRAC-PK proteins have a similar expression pattern, being regulated both maternally and zygotically, and are expressed throughout Drosophila development. Antisera specific for recombinant DRAC-PK and for its C terminus detected two polypeptides of 66 and 85 kDa in Drosophila extracts. The antirecombinant antisera also recognized a polypeptide of 120 kDa from Drosophila, which apparently shared an epitope related to DRAC-PK sequences. The role of p120 appears to be restricted compared with that of DRAC-PK, since it was not detected in larvae or adult flies. There was no spatial restriction of DRAC-PK expression during embryogenesis, suggesting that localized activation might be a regulatory mechanism for its function. DRAC-PK possesses an intrinsic kinase activity that is approximately 8-fold higher in adult flies than in 0-3-h embryos undergoing rapid mitotic cycles.

Amino Acid Sequence↗

PubMed1998

Caspase-14 is a novel developmentally regulated protease.

Caspases are a family of cysteine proteases related to interleukin-1 converting enzyme (ICE) and represent the effector arm of the cell death pathway. The zymogen form of all caspases is composed of a prodomain plus large and small catalytic subunits. Herein we report the characterization of a novel caspase, MICE (for mini-ICE), also designated caspase-14, that possesses an unusually short prodomain and is highly expressed in embryonic tissues but absent from all adult tissues examined. In contrast to the other short prodomain caspases (caspase-3, caspase-6, and caspase-7), MICE preferentially associates with large prodomain caspases, including caspase-1, caspase-2, caspase-4, caspase-8, and caspase-10. Also unlike the other short prodomain caspases, MICE was not processed by multiple death stimuli including activation of members of the tumor necrosis factor receptor family and expression of proapoptotic members of the bcl-2 family. Surprisingly, however, overexpression of MICE itself induced apoptosis in MCF7 human breast cancer cells, which was attenuated by traditional caspase inhibitors.

Amino Acid Sequence↗

PubMed2001

Collectrin, a collecting duct-specific transmembrane glycoprotein, is a novel homolog of ACE2 and is developmentally regulated in embryonic kidneys.

Collectrin, a novel homolog of angiotensin-converting enzyme-related carboxypeptidase (ACE2), was identified during polymerase chain reaction-based cDNA subtraction and up-regulated in 5/6 ablated kidneys at hypertrophic phase. Collectrin, with 222 amino acids, has an apparent signal peptide and a transmembrane domain; the sequence is conserved in mouse, rat, and human and shares 81.9% identity. Human collectrin has 47.8% identity with non-catalytic extracellular, transmembrane, and cytosolic domains of ACE2; however, unlike ACE and ACE2, collectrin lacks active dipeptidyl carboxypeptidase catalytic domains. The collectrin mRNA transcripts are expressed exclusively in the kidney. In situ hybridization reveals its mRNA expression in renal collecting ducts, and immunohistochemistry shows that it is localized to the luminal surface and cytoplasm of collecting ducts. Immunoprecipitation studies, using [35S]methionine-labeled renal cortical and inner medullar collecting duct cells, i.e. M-1 and mIMCD-3, indicate that the protein size is approximately 32 kDa. During the development of mouse kidney, mRNA signal is detectable at day 13 of gestation, and the protein product is observed in the ureteric bud branches. Its expression is progressively increased during later stages of the gestation extending into the neonatal periods and then is decreased in adult life. Up-regulated expression of collectrin in the hypertrophic kidneys after renal ablation and restricted spatio-temporal expression during development indicates a possible role(s)in the process of progressive renal failure and renal organogenesis.

Amino Acid Sequence↗

PubMed1997

Stress and developmental regulation of the yeast C-type cyclin Ume3p (Srb11p/Ssn8p).

The ume3-1 allele was identified as a mutation that allowed the aberrant expression of several meiotic genes (e.g. SPO11, SPO13) during mitotic cell division in Saccharomyces cerevisiae. Here we report that UME3 is also required for the full repression of the HSP70 family member SSA1. UME3 encodes a non-essential C-type cyclin (Ume3p) whose levels do not vary through the mitotic cell cycle. However, Ume3p is destroyed during meiosis or when cultures are subjected to heat shock. Ume3p mutants resistant to degradation resulted in a 2-fold reduction in SPO13 mRNA levels during meiosis, indicating that the down-regulation of this cyclin is important for normal meiotic gene expression. Mutational analysis identified two regions (PEST-rich and RXXL) that mediate Ume3p degradation. A third destruction signal lies within the highly conserved cyclin box, a region that mediates cyclin-cyclin-dependent kinase (Cdk) interactions. However, the Cdk activated by Ume3p (Ume5p) is not required for the rapid destruction of this cyclin. Finally, Ume3p destruction was not affected in mutants defective for ubiquitin-dependent proteolysis. These results support a model in which Ume3p, when exposed to heat shock or sporulation conditions, is targeted for destruction to allow the expression of genes necessary for the cell to respond correctly to these environmental cues.

Adenosine Triphosphatases↗

PubMed2001

Nuclear DNA polymerase beta from Leishmania infantum. Cloning, molecular analysis and developmental regulation.

We have identified a novel polymerase beta (Pol beta)-like enzyme from Leishmania infantum, a parasite protozoon causing disease in humans. This protein, named Li Pol beta, shows a nuclear localization that contrasts with the mitochondrial localization of Pol beta from Crithidia fasciculata, a closely related parasite, the only polymerase beta described so far in Trypanosomatidae. Li Pol beta, that belongs to the DNA polymerase X family, displays an evolutionarily conserved Pol beta-type DNA polymerase core, in which most of the key residues involved in DNA binding, nucleotide binding, dRPase and polymerization catalysis are conserved. In agreement with this, Li Pol beta, overproduced in Escherichia coli, displayed intrinsic DNA polymerase activity. Cell synchronization experiments showed a correlation between both Li Pol beta mRNA and protein levels along the parasite cell cycle. Analysis of these parameters at the different growth phases of the parasite, from the proliferative (non-infective) logarithmic phase to the non-dividing (highly infectious) stationary phase, showed high levels of Li Pol beta at the infective phase of the parasite. The data suggest a role of Li Pol beta in base excision repair in L.infantum, a parasite usually affected by oxygen stress environments into the macrophage host cells.

Amino Acid Sequence↗

PubMed1999

Molecular cloning and characterization of two zebrafish alpha(1,3)fucosyltransferase genes developmentally regulated in embryogenesis.

Some alpha(1,3)fucosylated oligosaccharides serve as counter receptors to lectin-like adhesion proteins or are expressed with temporal precision during embryogenesis, and alpha(1, 3)fucosyltransferase is a key enzyme in the production of these oligosaccharides. Two alpha(1,3)-fucosyltransferase genes, designated zFT1 and zFT2, were cloned from zebrafish. Sequence comparisons with other genes indicated that zFT1 and zFT2 share about 30% amino acid sequence identity with human alpha(1, 3)fucosyltransferases. Although the alpha(1,3)fucosyltransferases cloned so far can be classified into three types-myeloid, Lewis, and leukocyte-by virtue of their amino acid sequences, phylogenetic analysis indicated that neither zFT1 nor zFT2 belongs to any of these categories. The expression of zFT1 or zFT2 in mammalian cells induces alpha(1,3)fucosyltransferase activity to synthesize the Lewis x structure from pyridylaminated lacto-N-neotetraose; however, lacto-N-tetraose does not serve as a substrate. Reverse transcriptase-polymerase chain reaction analysis revealed that zFT1 is transcribed during a restricted period before hatching, whereas the mRNA for zFT2 was detected only after hatching.

Amino Acid Sequence↗

PubMed2002

OSTF1: a HD-GL2 family homeobox gene is developmentally regulated during early embryogenesis in rice.

In many eukaryotic organisms, homeobox genes are important regulators that specify the cell fate and body plan in early embryogenesis. In this study, a gene designated OSTF1 (Oryza sativa transcription factor 1) encoding a homeodomain protein in rice was isolated and characterized. The encoded OSTF1, although sharing only approximately 51% sequence identity with other HD-GL2 members, contains four characteristic motifs (an N-terminal acidic region, a homeodomain, a truncated leucine zipper, and a START domain). OSTF1 was detected as a single copy gene in rice. The transcripts were absent in young panicle or mature spikelet before anthesis, but appeared very early in the pollinated grain with a transient profile. In vegetative tissues examined, expression was only detectable in root. In situ hybridization analysis on developing grains revealed that OSTF1 was strongly and uniformly expressed in the embryo at the globular stage and preferentially localized to the protoderm at 3-6 d after pollination. Expression was also detectable in the integument and throughout the endosperm. Although OSTF1 is not closely related to the remaining HD-GL2 members in sequences, this gene exhibits an analogous epidermis-preferential expression pattern.

Amino Acid Sequence↗

PubMed1997

Isolation of developmentally regulated genes from the edible mushroom Agaricus bisporus.

From a cDNA library, constructed from mushroom primordia, nine cDNAs were isolated which were either induced or specifically expressed during fruit body development and maturation of the basidiomycete Agaricus bisporus. These cDNAs varied in size from 372 to 1019 bp and hybridized to transcripts of 400-1600 nt. Four of the cDNAs were only expressed in the generative phase of the life cycle while the other five cDNAs were strongly induced but had low steady-state mRNA levels in vegetatively grown mycelium of the hybrid strain Horst U1. An apparent full-length cDNA could be identified by sequence analysis and specified a putative protein homologous to the delta-subunit of the mitochondrial ATP synthase complex of Saccharomyces cerevisiae and Neurospora crassa. For one of the partial cDNAs, significant homology was found with a family of cell division control proteins, while another partial cDNA appeared to encode a cytochrome P450. All cDNAs, except the presumed cytochrome-P450-specifying cDNA (cypA), hybridized with single copy genes scattered over the Agaricus genome. For the cypA gene, the presence of several additional copies was shown by heterologous hybridizations. Based on changes in expression levels of the fruit-body-induced genes during development coinciding with alterations in morphological appearance of mushrooms, four stages of development were distinguished during growth and maturation of A. bisporus fruit bodies.

Agaricus↗