Science_-_6_March_2020

CREDITS (FROM T0P) HAGE

ET AL

.; HOU

ET AL

.

1086 6 MARCH 2020 • VOL 367 ISSUE 6482 sciencemag.org SCIENCE

screen using CRISPR-Cas9

with single-cell transcriptomics

suggested critical roles for

hundreds of micropeptides.

Micropeptides encoded by

multiple short, upstream ORFs

form stable protein complexes

with the downstream canonical

proteins encoded on the same

messenger RNAs. —SYM

Science, this issue p. 1140;

see also p. 1074

TRANSCRIPTION

RNA life span at

single-cell resolution

RNA transcripts are an eas-

ily accessed representation of

gene expression, but we lack a

comprehensive view of the life

span of RNA within the single

cell. Battich et al. developed

a method to sequence mes-

senger RNA labeled with

QUANTUM SIMULATION

Gauge invariance

with cold atoms

There is considerable inter-
est in developing quantum
computational technologies
that can simulate a series of
physical phenomena inacces-
sible by classical computers.
Mil et al. propose a modular
scheme for quantum simulation
of a U(1) lattice gauge theory
based on heteronuclear spin-
changing collisions in a mixture
of two bosonic quantum gases
isolated in single wells of a one-
dimensional optical lattice. They
engineered the elementary
building block for a single well
and demonstrate its reliable
operation that preserves the
gauge invariance. The potential
for scalability of the proposed
scheme opens up opportuni-
ties to address challenges

RESEARCH

in quantum simulating the

continuum limit of the gauge

theories. —YS

Science, this issue p. 1128

HIV

Clearing a path for

an HIV cure

Curing HIV is more feasible if we

better understand the forma-

tion of the latent viral reservoir.

Leyre et al. studied longitudi-

nal blood and tissue samples

obtained from individuals during

acute HIV infection. The large

pool of infected cells present

at the early stages of infection

did not survive antiretroviral

treatment. Infected cells at later

stages were more prevalent in

lymphoid tissues than in blood.

These results show that most

infected targets are cleared

with early treatment, but

HIV-positive cells that remain

after a certain stage are more

likely to persist. These persis-

tent cells are the ones that will

need to be eradicated for a cure

to be achieved. —LP

Sci. Transl. Med. 12 , eaav3491 (2020).

MOLECULAR BIOLOGY

Expanding the human

proteome

Using mass spectrometry,

ribosome profiling, and several

CRISPR-based screens, Chen

et al. identified hundreds of

previously uncharacterized

functional micropeptides in

the human genome (see the

Perspective by Wei and Guo).

Pro tein translation outside of

annotated open reading frames

(ORFs) in messenger RNAs and

within ORFs in long noncoding

RNAs is pervasive. A functional

IN SCIENCE JOURNALS

Edited by Michael Funk

SOLAR CELLS

Growing perovskite on textured silicon

W

ide–band gap perovskites could boost the efficiency of

silicon solar cells by forming tandem cells, but usually the

perovskite must be grown on a smoothed side of the silicon

cell because the material grown on the rough light-trapping

side often does not fully coat the silicon surface and its

rough texture is prone to phase separation. Hou et al. grew thick

films of a perovskite with a band gap of ~1.68 electron volts and

used a passivant, 1-butanethiol, to limit its phase separation. The

tandem cells had a certified power conversion efficiency of

25.7% and had negligible losses after 400 hours of operation.

—PDS Science, this issue p. 1135

Cross-sectional scanning electron microscope image of textured crystalline

silicon, which can form the bottom cell in perovskite-silicon tandem solar cells

Vibrational spectroscopy in

an electron microscope

Hage et al.,p. 1124

Published by AAAS