Disease relevance of Haploidy

• Deletion of the kinase domain of STE20 causes sterility in both haploid mating types [1].
• Analysis of both total genomic DNAs and an ATIII gene cloned in a bacteriophage Charon 4A showed that the ATIII gene is present once per haploid genome and is distributed over 10-16 kilobases of DNA [2].
• The defect in replication is apparently a consequence of a deletion in one or more viral genes: the haploid genome of the MC29 virus has a molecular weight of ca. 1.7 X 10(6), whereas the genome of the helper virus MCAV has a molecular weight of ca. 3.1 X 10(6) [3].
• Using haploid recombinant selection and analysis procedures similar to those applied to Streptomyces coelicolor A3(2), 14 auxotrophic markers and 1 streptomycin resistance marker were located on a circular linkage map [4].
• The frequency of auxotrophic mutants and histidine requiring (His-) haploid colonies was increased by mutagen treatment but Hfr colonies were not detected in F30 E. coli even with specific selection techniques [5].

High impact information on Haploidy

• Haploid markers from mitochondrial DNA and the Y chromosome have proven invaluable for generating a standard model for evolution of modern humans [6].
• The role of homologous recombination is further evidenced in haploid cells in which both Sgs1p and Srs2p are absent [7].
• The alpha2 repressor is a known ubiquitin pathway substrate in alpha haploid cells [8].
• Cells of the 15P-1 type support the meiotic and postmeiotic differentiation in cocultures of diploid premeiotic germ cells into haploid spermatids expressing the protamine (Prm-1) gene [9].
• The STE4 and STE18 genes are required for haploid yeast cell mating [10].

Chemical compound and disease context of Haploidy

• Bacillus subtilis strains possessing the trpE30 marker (splitting of the trpE locus and a non-tandem duplication of chromosome segment Ib: purB-tre) when transformed or transduced to tryptophan independence mainly give rise to haploid cells with the genetic structure of strain 168 [11].

Biological context of Haploidy

• beta 2-Microglobulin is encoded by a single gene per haploid genome in the mouse [12].
• If such spores contain chimeric mammalian/yeast RAS genes or even the mammalian H-ras gene under the control of the galactose-inducible GAL10 promoter, they will germinate in the presence of galactose and produce viable haploid progeny dependent on galactose for continued growth and viability [13].
• In contrast with the dispersed organization of tubulin genes in other organisms, trypanosome alpha- and beta-tubulin genes are physically linked and clustered in tandem repeats of approximately 13-17 copies per haploid genome of alternating alpha- and beta-tubulin sequences [14].
• Transcription of the HO gene is start-dependent and restricted to the late G1/early S phase of haploid mother cells [15].
• The signal transduction pathway that mediates the response of haploid yeast cells to peptide mating pheromones involves several components including the protein kinases STE7 and STE11 [16].

Anatomical context of Haploidy

• Disruption of T cell signaling networks and development by Grb2 haploid insufficiency [17].
• We show that a haploid dose of GATA-2 severely reduces production and expansion of HSCs specifically in the aorta-gonad-mesonephros region (which autonomously generates the first HSCs), whereas quantitative reduction of HSCs is minimal or unchanged in yolk sac, fetal liver, and adult bone marrow [18].
• Besides the brain, transcripts for Lis1, alpha1, and alpha2 are localized to meiotic and early haploid germ cells [19].
• As a result, the aquaporin null cells were more flocculent and more efficient at haploid invasive growth [20].
• Using a Drosophila haploid cell line for transient expression, we found that trithorax or Polycomb can function independently through this upstream fragment to activate or repress the Ultrabithorax promoter, respectively [21].

Associations of Haploidy with chemical compounds

• Cytogenetic analysis of 26 PTC and 5 FTC showed clonal abnormalities in 9 and included -Y, +5, or inv(10)(q11.2q21.2) in PTC, and -Y or near haploidy in FTC [22].
• The gene encoding neuraxin appears to be unique in the haploid rat genome and conserved in higher vertebrates [23].
• MMS survival of haploid cdc2-2 strains is lower than wild type at the permissive growth temperature of 20 degrees C. Survival is further decreased relative to wild type by treatment with MMS at 36 degrees C, a nonpermissive temperature for growth of mutant cells [24].
• Yeast strains deleted for TEP1 exhibit essentially no phenotype in haploids; however, diploids exhibit resistance to the phosphatidylinositol-3-phosphate kinase inhibitor wortmannin and to lithium ions [25].
• Disruption of the MDH2 gene in a haploid strain also containing a disruption in the chromosomal MDH1 gene encoding the mitochondrial isozyme produced a strain unable to grow with acetate but capable of growth on rich medium with glycerol as a carbon source [26].

Gene context of Haploidy

• Deleting NEJ1 reduces NHEJ 100-fold in MATa or MAT alpha haploids [27].
• The function of the PMA1 gene is essential because a null mutation is lethal in haploid cells [28].
• One such gene, AXL2, has been characterized in detail. axl2 cells are defective in bud site selection in haploid cells and bud in a bipolar fashion [29].
• A pol3-01/pol3-01 pms1/pms1 diploid was viable and displayed an estimated URA3 relative mutation rate of 2 x 10(4), which we calculate to be catastrophically high in a haploid [30].
• These results are consistent with the idea that STE2 encodes an alpha-factor receptor and STE3 encodes an a-factor receptor, and suggest that both alpha- and a-factors may generate an exchangeable signal(s) within haploid cells [31].

Analytical, diagnostic and therapeutic context of Haploidy

• Molecular cloning and sequence analysis of a haploid expressed gene encoding t complex polypeptide 1 [32].
• Restriction mapping experiments further suggested the existence of a single J chain gene per haploid genome [33].
• The presence of both alpha- and beta-tryptase sequences in each haploid genome was indicated by finding alpha- and beta-tryptase specific fragments after amplification by PCR of genomic DNA in 10 unrelated individuals [34].
• Southern blot analysis suggests that the CSF-1 gene is present as a single copy in the mouse haploid genome and that it is not rearranged or amplified in L cells [35].
• Various Snf1/Gal83-dependent processes were upregulated, including glycogen accumulation, expression of RNAs encoding glycogen synthase, haploid invasive growth, the transcriptional activator function of Sip4, and activation of the carbon source-responsive promoter element [36].

References