Delivery rates after elective single cryopreserved embryo transfer related to embryo survival.

Objective: The objective of this study was to assess if eSCET (elective Single Cryopreserved Embryo Transfer) outcome is related to blastomere survival rate. The final objective was to avoid multiple pregnancies and offer the best chances to women to achieve pregnancy even during their frozen-thawed embryo transfer (FET) cycles.

Study Design: Patients were included in this prospective observational study if they met the following criteria: (i) women age <37 years old; (ii) IVF of ICSI cycle rank ≤2, (iii) eSET proposed during fresh embryo transfer cycle and (iv) ≥1 good quality cryopreserved embryos available (<20% fragmentation and 4-5 blastomeres at day-2 or 7-9 blastomeres at day-3).

Two maize END-1 orthologs, BETL9 and BETL9like, are transcribed in a non-overlapping spatial pattern on the outer surface of the developing endosperm.

In the course of a project aimed to isolate transfer cells-specific genes in maize endosperm we have identified the BETL9 gene. BETL9 encodes for a small protein very similar in sequence to the product of the barley transfer cell-specific gene END-1. Both BETL9 and END-1 proteins are lipid transfer proteins, but their function is currently unknown.

A PCR-based forward genetics screening, using expression domain-specific markers, identifies mutants in endosperm transfer cell development.

Mutant collections are an invaluable source of material on which forward genetic approaches allow the identification of genes affecting a wide variety of biological processes. However, some particular developmental stages and morphological structures may resist analysis due to their physical inaccessibility or to deleterious effects associated to their modification. Furthermore, lethal mutations acting early in development may escape detection.

The maize transcription factor myb-related protein-1 is a key regulator of the differentiation of transfer cells.

Transfer cells are highly modified plant cells specialized in the transport of solutes. They differentiate at many plant exchange surfaces, including phloem loading and unloading zones such as those present in the sink organs and seeds. In maize (Zea mays) seeds, transfer cells are located at the base of the endosperm.

empty pericarp4 encodes a mitochondrion-targeted pentatricopeptide repeat protein necessary for seed development and plant growth in maize.

The pentatricopeptide repeat (PPR) family represents one of the largest gene families in plants, with >440 members annotated in Arabidopsis thaliana. PPR proteins are thought to have a major role in the regulation of posttranscriptional processes in organelles. Recent studies have shown that Arabidopsis PPR proteins play an essential, nonredundant role during embryogenesis.