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Precise regulation of transcription by RNA polymerase II (RNAPII) is critical for organismal growth and development. However, what determines whether an engaged RNAPII will synthesize a full-length transcript or terminate prematurely is poorly understood. Notably, RNAPII is far more susceptible to termination when transcribing non-coding RNAs than when synthesizing protein-coding mRNAs, but the mechanisms underlying this are unclear. To investigate the impact of transcribed sequence on elongation potential, we developed a method to screen the effects of thousands of INtegrated Sequences on Expression of RNA and Translation using high-throughput sequencing (INSERT-seq). We found that higher AT content in non-coding RNAs, rather than specific sequence motifs, drives RNAPII termination. Further, we demonstrate that 5′ splice sites autonomously stimulate processive transcription, even in the absence of polyadenylation signals. Our results reveal a potent role for the transcribed sequence in dictating gene output and demonstrate the power of INSERT-seq toward illuminating these contributions.

Splicing modulation is a promising treatment strategy pursued to date only in splicing factor-mutant cancers; however, its therapeutic potential is poorly understood outside of this context. Like splicing factors, genes encoding components of the cohesin complex are frequently mutated in cancer, including myelodysplastic syndromes (MDS) and secondary acute myeloid leukemia (AML), where they are associated with poor outcomes. Here, we showed that cohesin mutations are biomarkers of sensitivity to drugs targeting the splicing factor 3B subunit 1 (SF3B1) H3B-8800 and E-7107. We identified drug-induced alterations in splicing, and corresponding reduced gene expression, of a number of DNA repair genes, including BRCA1and BRCA2, as the mechanism underlying this sensitivity in cell line models, primary patient samples and patient-derived xenograft (PDX) models of AML. We found that DNA damage repair genes are particularly sensitive to exon skipping induced by SF3B1 modulators due to their long length and large number of exons per transcript. Furthermore, we demonstrated that treatment of cohesin-mutant cells with SF3B1 modulators not only resulted in impaired DNA damage response and accumulation of DNA damage, but it sensitized cells to subsequent killing by poly(ADP-ribose) polymerase (PARP) inhibitors and chemotherapy and led to improved overall survival of PDX models of cohesin-mutant AML in vivo. Our findings expand the potential therapeutic benefits of SF3B1 splicing modulators to include cohesin-mutant MDS and AML.

The objectives of this study are to test the hypothesis that stillbirths without aneuploidy-associated phenotypes have a low incidence of karyotypic abnormalities, similar among those with and without other anatomic defects. We employed a uniform postmortem protocol to examine fetuses and placentas in 962 consecutive stillbirths measuring ≥20 weeks in clinically determined gestational age submitted to the Women and Infants Hospital Division of Perinatal Pathology from 1990 through 2005. Classification of anatomic (macroscopic) abnormalities was based on a priori criteria. Anatomic fetal abnormalities were noted in 387 cases. Conventional karyotype analysis was successfully performed on 346 fetal tissue samples, 114 in anatomically normal and 232 in anatomically abnormal fetuses. The distribution of karyotypic abnormalities among cases with and without anatomic abnormalities was compared. Of the 962 stillbirths, 40% (387) had malformations. Tissue culture for karyotype analysis was attempted in 412 cases from both groups and failed in 66 cases (16%). At the 450 to 500-band resolution level, 60 of the remaining 346 karyotypes were abnormal. Of the 232 malformation cases with successful karyotyping, 59 had phenotypic attributes indicative of aneuploidy, all of which had later karyotype confirmation. Of the remaining 173 anomalous fetuses with karyotype analysis, only 1 demonstrated a karyotypic abnormality. All 114 karyotypes performed in stillbirths without anatomic abnormalities were normal. Among ≥20-week stillbirths, aneuploid karyotypes are uncommon except in fetuses with suspect phenotypes. The 95% probability estimates of karyotype abnormality in the phenotypically abnormal and normal stillbirths, 5.5% and 5.6%, respectively, do not differ. These data do not have sufficient power to detect a small difference in rates of karyotypic abnormalities between the 2 groups of ≥20-week stillbirths. However, this series indicates that this technology is uninformative among stillborn fetuses that lack aneuploidy phenotypes.

This article analyzes cesarean hysterectomies performed at Louisville General Hospital on clinic patients for the 25 year period 1953 through 1977. During this time there were 63,259 deliveries, of which 2417 were cesarean sections and 149 were cesarean hysterectomies. Twenty-six of the latter were classified as emergency operations done for urgent medical indications; in the remaining 123 patients the indications were elective to some degree. Operative and postoperative complications and morbidity are discussed, and changing trends regarding the place of cesarean hysterectomy in obstetrics over the years are evaluated.