The molecular motor protein CHD1 has been implicated in the regulation of 
transcription and in the transcription-independent genome-wide incorporation of 
H3.3 into paternal chromatin in Drosophila melanogaster. A key feature of CHD1 
is the presence of two chromodomains, which can bind to histone H3 methylated at 
lysine 4 and thus might serve to recruit and/or maintain CHD1 at the chromatin. 
Here, we describe genetic and biochemical approaches to the study of the 
Drosophila CHD1 chromodomains. We found that overall localization of CHD1 on 
polytene chromosomes does not appreciably change in chromodomain-mutant flies. 
In contrast, the chromodomains are important for transcription-independent 
activities of CHD1 during early embryonic development as well as for 
transcriptional regulation of several heat shock genes. However, neither CHD1 
nor its chromodomains are needed for RNA polymerase II localization and H3K4 
methylation but loss of CHD1 decreases transcription-induced histone eviction at 
the Hsp70 gene in vivo. Chromodomain mutations negatively affect the chromatin 
assembly activities of CHD1 in vitro, and they appear to be involved in linking 
the ATP-dependent motor to the chromatin assembly function of CHD1.