Only the Rye Derived Part of the 1BL/1RS Hybrid Centromere Incorporates CENH3 of Wheat

The precise assembly of the kinetochore complex at the centromere is epigenetically determined by substituting histone H3 with the centromere-specific histone H3 variant CENH3 in centromeric nucleosomes. The wheat-rye 1BL/1RS translocation chromosome in the background of wheat resulted from a centric misdivision followed by the fusion of the broken arms of chromosomes 1B and 1R from wheat and rye, respectively. The resulting hybrid (dicentric)centromere is composed of both wheat and rye centromeric repeats. As CENH3 is a marker for centromere activity, we applied Immuno-FISH followed by ultrastructural super-resolution microscopy to address whether both or only parts of the hybrid centromere are active. Our study demonstrates that only the rye-derived centromere part incorporates CENH3 of wheat in the 1BL/1RS hybrid centromere. This finding supports the notion that one centromere part of a translocated chromosome undergoes inactivation, creating functional monocentric chromosomes to maintain chromosome stability.

IgM-MM is predominantly a pre–germinal center disorder and has a distinct genomic and transcriptomic signature from WM

Immunoglobulin M (IgM) multiple myeloma (MM) is a rare disease subgroup. Its differentiation from other IgM-producing gammopathies such as Waldenström macroglobulinemia (WM) has not been well characterized but is essential for proper risk assessment and treatment. In this study, we investigated genomic and transcriptomic characteristics of IgM-MM samples using whole-genome and transcriptome sequencing to identify differentiating characteristics from non–IgM-MM and WM. Our results suggest that IgM-MM shares most of its defining structural variants and gene-expression profiling with MM, but has some key characteristics, including t(11;14) translocation, chromosome 6 and 13 deletion as well as distinct molecular and transcription-factor signatures. Furthermore, IgM-MM translocations were predominantly characterized by VHDHJH recombination-induced breakpoints, as opposed to the usual class-switching region breakpoints; coupled with its lack of class switching, these data favor a pre–germinal center origin. Finally, we found elevated expression of clinically relevant targets, including CD20 and Bruton tyrosine kinase, as well as high BCL2/BCL2L1 ratio in IgM-MM, providing potential for targeted therapeutics.

Identification and Characterization of Wheat - Aegilops Comosa 7M/7A Disomic Substitution Lines with Stripe Rust Resistance

Aegilops comosa (MM, 2n = 2x = 14), an important diploid species belonging to wheat tertiary gene pools, contains many excellent genes/traits, including disease resistance for wheat breeding. In this study, three sister lines, NAL-32, NAL-33, and NAL-34, were identified from a wheat - Ae. comosa distant cross using fluorescence in situ hybridization (FISH) combined with single nucleotide polymorphism (SNP) microarray analysis. Genetically, NAL-32 contained neither an alien nor translocation chromosome, whereas NAL-33 and NAL-34 had disomic 7M/7A substitution chromosomes but differed in the absence (NAL-33) or presence (NAL-34) of 1BL/1RS translocation chromosomes. The substitution of 7M/7A in NAL-33 and NAL-34 was verified using wheat 55 K SNP arrays but 1BL/1RS translocation in NAL-34 was not. The two 7M/7A substitution lines, NAL-33 and NAL-34, had similar stripe rust resistance, and both showed higher stripe rust resistance than NAL-32 and their parents, suggesting that stripe rust resistance in NAL-33 and NAL-34 was derived from the 7M of Ae. comosa and that their resistance was likely irrelevant to 1BL/1RS translocation. Meanwhile, the three NAL lines also showed higher grain weights (grams per 50 grains) than one to three of their three wheat parents, and the two 7M/7A substitution lines, NAL-33 and NAL-34, had larger seed size-related traits than NAL-32, suggesting that both the 7M and 1BL/1RS chromosomes had positive effects on seed size-related traits. The results provide important bridge materials that can potentially be used for transferring stripe rust resistance, as well as seed size-related traits from Ae. comosa to wheat.

SS18 is a differentially expressed gene in brain metastatic human breast cancer.

Metastasis to the brain is a clinical problem in patients with breast cancer (1-3). We mined published microarray data (4, 5) to compare primary and metastatic tumor transcriptomes for the discovery of genes associated with brain metastasis in humans with metastatic breast cancer. We found that synovial sarcoma translocation, chromosome 18, encoded by SS18, was among the genes whose expression was most different in the brain metastases of patients with metastatic breast cancer as compared to primary tumors of the breast. SS18 mRNA was present at decreased quantities in brain metastatic tissues as compared to primary tumors of the breast. Importantly, expression of SS18 in primary tumors was correlated with patient post-progression survival. Modulation of SS18 expression may be relevant to the biology by which tumor cells metastasize from the breast to the brain in humans with metastatic breast cancer.

Homology-mediated inter-chromosomal interactions in hexaploid wheat lead to specific subgenome territories following polyploidization and introgression

Background Polyploidization and introgression are major events driving plant genome evolution and influencing crop breeding. However, the mechanisms underlying the higher-order chromatin organization of subgenomes and alien chromosomes are largely unknown. Results We probe the three-dimensional chromatin architecture of Aikang 58 (AK58), a widely cultivated allohexaploid wheat variety in China carrying the 1RS/1BL translocation chromosome. The regions involved in inter-chromosomal interactions, both within and between subgenomes, have highly similar sequences. Subgenome-specific territories tend to be connected by subgenome-dominant homologous transposable elements (TEs). The alien 1RS chromosomal arm, which was introgressed from rye and differs from its wheat counterpart, has relatively few inter-chromosome interactions with wheat chromosomes. An analysis of local chromatin structures reveals topologically associating domain (TAD)-like regions covering 52% of the AK58 genome, the boundaries of which are enriched with active genes, zinc-finger factor-binding motifs, CHH methylation, and 24-nt small RNAs. The chromatin loops are mostly localized around TAD boundaries, and the number of gene loops is positively associated with gene activity. Conclusions The present study reveals the impact of the genetic sequence context on the higher-order chromatin structure and subgenome stability in hexaploid wheat. Specifically, we characterized the sequence homology-mediated inter-chromosome interactions and the non-canonical role of subgenome-biased TEs. Our findings may have profound implications for future investigations of the interplay between genetic sequences and higher-order structures and their consequences on polyploid genome evolution and introgression-based breeding of crop plants.

Molecular and Cytogenetic Characterization of a Wheat-Rye 7BS.7RL Translocation Line with Resistance to Stripe Rust, Powdery Mildew, and Fusarium Head Blight

Secale cereale is used as a source of genes for disease resistance in wheat cultivation. In this study, a homozygous translocation line (RT14-245) that originated from a cross between a commercial wheat cultivar (Mianyang 11) and a local Chinese variety of rye (Baili) was developed. Multicolor fluorescence in situ hybridization and PCR analysis demonstrated that the translocation chromosome was 7BS.7RL. Resistance analysis showed that RT14-245 was resistant to prevalent pathotypes of stripe rust and powdery mildew. RT14-245 also exhibited high resistance to Fusarium head blight, which was similar to the resistance exhibited by the wheat cultivar Sumai 3. The results indicated that RT14-245 simultaneously exhibited high levels of resistance against stripe rust, powdery mildew, and Fusarium head blight. These results indicate that chromosome arm 7RL in the translocation line RT14-245 is an excellent new resource for wheat breeding programs.

A female patient with retinoblastoma and severe intellectual disability carrying an X;13 balanced translocation without rearrangement in the RB1 gene: a case report

Background Female carriers of a balanced X; autosome translocation generally undergo selective inactivation of the normal X chromosome. This is because inactivation of critical genes within the autosomal region of the derivative translocation chromosome would compromise cellular function. We here report a female patient with bilateral retinoblastoma and a severe intellectual disability who carries a reciprocal X-autosomal translocation. Case presentation Cytogenetic and molecular analyses, a HUMARA (Human androgen receptor) assay, and methylation specific PCR (MSP) and bisulfite sequencing were performed using peripheral blood samples from the patient. The patient’s karyotype was 46,X,t(X;13)(q28;q14.1) by G-banding analysis. Further cytogenetic analysis located the entire RB1 gene and its regulatory region on der(X) with no translocation disruption. The X-inactivation pattern in the peripheral blood was highly skewed but not completely selected. MSP and deep sequencing of bisulfite-treated DNA revealed that an extensive 13q region, including the RB1 promoter, was unusually methylated in a subset of cells. Conclusions The der(X) region harboring the RB1 gene was inactivated in a subset of somatic cells, including the retinal cells, in the patient subject which acted as the first hit in the development of her retinoblastoma. In addition, the patient’s intellectual disability may be attributable to the inactivation of the der(X), leading to a 13q deletion syndrome-like phenotype, or to an active X-linked gene on der (13) leading to Xq28 functional disomy.

Using the 6RLKu Minichromosome of Rye (Secale cereale L.) to Create Wheat-Rye 6D/6RLKu Small Segment Translocation Lines with Powdery Mildew Resistance

Long arms of rye (Secale cereale L.) chromosome 6 (6RL) carry powdery mildew resistance genes. However, these sources of resistance have not yet been successfully used in commercial wheat cultivars. The development of small segment translocation chromosomes carrying resistance may result in lines carrying the 6R chromosome becoming more commercially acceptable. However, no wheat-rye 6RL small segment translocation line with powdery mildew resistance has been reported. In this study, a wheat-rye 6RLKu minichromosome addition line with powdery mildew resistance was identified, and this minichromosome was derived from the segment between L2.5 and L2.8 of the 6RLKu chromosome arm. Following irradiation, the 6RLKu minichromosome divided into two smaller segments, named 6RLKumi200 and 6RLKumi119, and these fragments participated in the formation of wheat-rye small segment translocation chromosomes 6DS/6RLKumi200 and 6DL/6RLKumi119, respectively. The powdery mildew resistance gene was found to be located on the 6RLKumi119 segment. Sixteen 6RLKumi119-specific markers were developed, and their products were cloned and sequenced. Nucleotide BLAST searches indicated that 14 of the 16 sequences had 91–100% similarity with nine scaffolds derived from 6R chromosome of S. cereale L. Lo7. The small segment translocation chromosome 6DL/6RLKumi119 makes the practical utilization in agriculture of powdery mildew resistance gene on 6RLKu more likely. The nine scaffolds are useful for further studying the structure and function of this small segment.

CHRONIC MYELOID LEUKEMIA IN PREGNANCY

Chronic Myeloid Leukemia (CML) is one of leukemias characterized by abnormal growth of myeloid cells in bone marrow. The Philadelphia chromosome is diagnostic parameter for CML. This chromosome is t(9;22) (q32;q21), a translocation chromosome 9 and 22 relocates a portion of proto-oncogene c-ABL from chromosome 9 to BCR on chromosome 22. Chronic myeloid leukemia consisting of three phases; Chronic, Accelerating and the Blast crisis phase. The clinicaling symptoms of CML are hypercatabolism, splenomegaly, anemia, bruising and sign of Gout. Chronic myeloid leukemia in pregnancy shows a better prognosis than acute leukemia in pregnancy. Chronic myeloid leukemia has the risk of leukocytosis which can lead to uteroplacental insufficiency giving rise to various consequences: fetal growth retardation and perinatal mortality. Moreover, the therapy of CML should be carefully administered considering the fetal effects. Both sexes have the same risk, mostly in the range of 40 to 60 years old. In this case report, a 38-year-old pregnant female (G1P0A0) with 37 weeks of gestational age was diagnosed as CML on August 2013 and was treated with 500 mg of Cytodrox/Hydroxyurea twice to three times a day until January 2014. Laboratory evaluation on November 10th, 2014, showed leucocytes 449500/µL, erythrocytes 2.58.106/µL, hemoglobin 8.0 g/dL, thrombocytes 437,000/µL and hematocrit 23%. The peripheral blood smear showed normocytic normochromic erythrocytes, anisocytosis, ovalocytes, significantly increased leucocyte count, predominance polymorphonuclear series, all maturation series of myelocytes, 7% myeloblast, normal thrombocyte count and morphology. Based on these evaluations, the patient was diagnosed as CML. The evaluation of Neutrophil Alkaline Phosphatase (NAP) scored 1.