The cyclin–like uracil DNA glycosylase (UDG) of murine oocytes and its relationship to human and chimpanzee homologues

Hyaluronic Acid Binding Sperm Selection for assisted reproduction treatment (HABSelect): study protocol for a multicentre randomised controlled trial

INTRODUCTION

The selection of a sperm with good genomic integrity is an important consideration for improving intracytoplasmic sperm injection (ICSI) outcome. Current convention selects sperm by vigour and morphology, but preliminary evidence suggests selection based on hyaluronic acid binding may be beneficial. The aim of the Hyaluronic Acid Binding Sperm Selection (HABSelect) trial is to determine the efficacy of hyaluronic acid (HA)-selection of sperm versus conventionally selected sperm prior to ICSI on live birth rate (LBR). The mechanistic aim is to assess whether and how the chromatin state of HA-selected sperm corresponds with clinical outcomes-clinical pregnancy rate (CPR), LBR and pregnancy loss (PL).

METHODS AND ANALYSIS

Couples attending UK Centres will be approached, eligibility screening performed and informed consent sought. Randomisation will occur within 24 hours prior to ICSI treatment. Participants will be randomly allocated 1:1 to the intervention arm (physiological intracytoplasmic sperm injection, PICSI) versus the control arm using conventional methods (ICSI). The primary clinical outcome is LBR ≥37 weeks' gestation with the mechanistic study determining LBR's relationship with sperm DNA integrity. Secondary outcomes will determine this for CPR and PL. Only embryologists performing the procedure will be aware of the treatment allocation. Steps will be taken to militate against biases arising from embryologists being non-blinded. Randomisation will use a minimisation algorithm to balance for key prognostic variables. The trial is powered to detect a 5% difference (24-29%: p=0.05) in LBR ≥37 weeks' gestation. Selected residual sperm samples will be tested by one or more assays of DNA integrity.

ETHICS AND DISSEMINATION

HABSelect is a UK NIHR-EME funded study (reg no 11/14/34; IRAS REF. 13/YH/0162). The trial was designed in partnership with patient and public involvement to help maximise patient benefits. Trial findings will be reported as per CONSORT guidelines and will be made available in lay language via the trial web site (http://www.habselect.org.uk/).

TRIAL REGISTRATION NUMBER

ISRCTN99214271; Pre-results.

Phosphorylation of cyclin O, a novel cyclin family protein containing a cyclin-like domain, is involved in the activation of cyclin-dependent kinase 2

Cell cycles, ordered series of events modulating cell growth and division, are tightly regulated by complexes containing cyclin-dependent kinases (CDKs) and cyclins. Cyclin O is a novel cyclin family protein which interacts with CDK2. However, the molecular effects of cyclin O on the activity of CDK2 have not been fully evaluated. In this study, an interaction between cyclin O and CDK2 was identified by co-immunoprecipitation and the effect of cyclin O on the kinase activity of CDK2 was investigated using cyclin O point mutants. Co-immunoprecipitation was achieved using using HEK293 human embryonic kidney cells which were transiently transfected with vectors expressing cyclin O and CDK2, which revealed that cyclin O interacted with CDK2, particularly with the active form of endogenous CDK2. Cyclin O was expressed as several different bands with molecular weights between 45 and 50 kDa, possibly due to different post-translational modifications. When co-expressed with CDK2, cyclin O appeared as a band with a molecular weight of 50 kDa. Treatment with calf intestinal phosphatase reduced the intensity of the uppermost band. Mass spectroscopic analysis of cyclin O co-expressed with CDK2 revealed that the 81st serine residue of cyclin O was phosphorylated. The in vitro kinase activity of CDK2 phosphorylating histone H1 was markedly increased in the cells overexpressing cyclin O. This activity was reduced in cells overexpressing cyclin O, in which the 81st serine had been replaced with alanine (S81A). These results suggest that cyclin O is a novel cyclin family protein that regulates CDK2 kinase activity, which is mediated by the phosphorylation of the 81st serine residue of cyclin O.