The N-terminal domains of TRF1 and TRF2 regulate their ability to condense telomeric DNA.

TRF1 and TRF2 are key proteins in human telomeres, which, despite their similarities, have different behaviors upon DNA binding. Previous work has shown that unlike TRF1, TRF2 condenses telomeric, thus creating consequential negative torsion on the adjacent DNA, a property that is thought to lead to the stimulation of single-strand invasion and was proposed to favor telomeric DNA looping. In this report, we show that these activities, originating from the central TRFH domain of TRF2, are also displayed by the TRFH domain of TRF1 but are repressed in the full-length protein by the presence of an acidic domain at the N-terminus.

Identification of an agrin mutation that causes congenital myasthenia and affects synapse function.

We report the case of a congenital myasthenic syndrome due to a mutation in AGRN, the gene encoding agrin, an extracellular matrix molecule released by the nerve and critical for formation of the neuromuscular junction. Gene analysis identified a homozygous missense mutation, c.5125G>C, leading to the p.

A novel class of MYB factors controls sperm-cell formation in plants.

In contrast to animals, the plant male germline is established after meiosis in distinctive haploid structures, termed pollen grains. The germline arises by a distinct asymmetric division of the meiotic products . The fates of the resulting vegetative and generative cells are distinct.

Sperm cells of Zea mays have a complex complement of mRNAs.

Although double fertilization in angiosperm was discovered in 1898, we still know nothing about the proteins that mediate gamete recognition and fusion in plants. Because sperm are small and embedded within the large vegetative cell of the pollen grain, mRNAs from sperm are poorly represented in EST databases. We optimized fluorescence-activated cell sorting (FACS) in order to isolate Zea mays sperm free of contaminating vegetative cell cytoplasm, and constructed a cDNA library.

Double fertilization in maize: the two male gametes from a pollen grain have the ability to fuse with egg cells.

In flowering plants, two male gametes from a single pollen grain fuse with two female gametes, the egg and central cells, to form the embryo and endosperm, respectively. The question then arises whether the two male gametes fuse randomly with the egg and central cells. We investigated this question using two nearly isogenic maize lines with supernumerary B chromosomes (TB10L18) or without (r-tester).